A STUDY OF THE QUALITY OF LENCAM FISH SKIN TANNED WITH NATURAL-CHEMICAL MIXTURES AS RAW MATERIALS FOR COMMERCIAL LEATHER PRODUCTS

Sahubawa L*¹, Lutfia S¹, Permadi I¹, Ekantari N¹

1) Departement of Fisheries, Faculty of Agriculture, Gadjah Mada University Flora Street No. 01, Bulaksumur UGM Campus, Yogyakarta-Indonesia, 55281

* Corresponding author: lsahubawa@ugm.ac.id

Fish skin can be tanned into collagen fibers as a raw material for commercial leather products. The research objectives were the tanning of lencam fish skin for commercial products, quality analysis and the added value. The treatment of the chemical-natural tanning mixture used was: 6% formalin (control) (p1), a mixture of 2% glutaraldehyde + 4% mimose (p2), a mixture of 4% glutaraldehyde + 4% mimose (p3) and a mixture of 6% glutaraldehyde + 4% mimosa (p4). The research method used are tanning, extraction, laboratory and added value. The quality level of fish skin is thickness (0.63 mm); tensile strength (3,920.30 N/cm2); tear strength (732.67 N/cm), Elongation (81.50%); Enervation (4.43 mm); wrinkle temperature (64.28°C); Water content (22.70%); fat content (11.35%). Quality parameters (thickness, tensile strength and tear strength) meets the SNI 06-4586-1998 and the Enervation meets Burk's Bay Suede Leather standard. The best treatment for the mixture of tannery materials, respectively: p1, p2, p4 and p3. The tanned lencam fish skin can be processed into commercial leather products (type 3-in-1) at a price of IDR 500,000 per item. The added value of 20 pieces obtained is IDR 172,500 in 2nd market segment and IDR 2,794,500 in 3st market segment.

Key words: fish skin, tanning, mimosa, glutaraldehyde, quality, value-added

BIOCHEMICAL COMPOSITION OF PACIFIC OYSTERS (Crassostrea gigas) FROM TWO MAIN CULTIVATION AREAS IN KHANH HOA PROVINCE, VIETNAM

Viet T. N. T. Bui¹*, Duong T.H. Ngo², Hai T.M. Pham², Huyen T. Tran¹, Giang T. Tran¹, Sanh K. Nguyen^,3

¹Food Technology Faculty, Nha Trang University, 02 Nguyen Dinh Chieu, Nha Trang City, Khanh Hoa Province, Viet Nam

²Institute of Biotechnology and Environment, Nha Trang University, 02 Nguyen Dinh Chieu, Nha Trang City, Khanh Hoa Province, Viet Nam

³Co phan Thuy san sinh hoc Vina Company, 163 Nguyen Trai, Nha Trang City, Khanh Hoa Province, Vietnam

^*Corresponding author: thanhviet@ntu.edu.vn

Pacific oysters are increasing market demand owing to their nutritional value. There are many areas in Khanh Hoa province cultivating these species but few results on the chemical composition have been published. This study aimed to evaluate the nutritional composition including moisture, total protein, glycogen, ash, total fat, fatty acids, amino acids and minerals of Crassostrea gigas from Van Ninh (VN) and Ninh Hoa (NH) of Khanh Hoa province over 2 seasons (dry and rainy season). Other components such as heavy metal and bacteria were also measured. The results showed that all nutritional components were higher in the dry season (from February to August) than those in the rainy season (from September to January). Whereas, the bacteria level in oyster meat from two areas were lower in samples collected in the dry season than in the rainy season. Protein was the major component in meat. It was around 12% in the dry season and 7% in the wet season and there was no significant difference between NH and VN. The content of total lipid showed no significant difference between samples collected from NH and VH. However, the proportions of total polyunsaturated fatty acids, eicosapentaenoic, and docosahexaenoic acids collected from VN were lower than those collected from NH. However, the Zinc content of oyster from VN (90.6 mg/kg) was much higher than that from NH (49.5 mg/kg). In addition, the oysters  were rich in essential amino acids (lysine, leucine, taurine). Glutamate was the predominant component of total amino acid in oysters, at concentrations of 1109 (mg/100g). The heavy metal (Pb, Hg, Cd) levels in oyster meat from two mentioned areas were lower than the allowable limit that according to the national technical regulation on limits of heavy metal contamination in food (QCVN 8-2:2011/BYT).

Keywords: Crassostrea gigas, oyster meat, nutritional value, biochemical composition

BIOLOGICAL ACTIVITIES OF PEPTIDE FRACTIONS ISOLATED FROM PHILIPPINES MUSSEL SPECIES THROUGH ENZYMATIC HYDROLYSIS

Sharon N. Nuñal*, Raymund B. Parcon, Sheina Logronio, Nizzy Hope Cartago, May Flor Muegue

Institute of Fish Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visaya, Miagao, Iloilo, Philippines

*Corresponding author: snnunal@up.edu.ph

Aside from its high protein content, mussels also contain a variety of biologically active compounds which can be derived from its proteins, lipids and other components. In this study, peptide fractions and hydrolysates obtained by enzymatic hydrolysis of proteins isolated from the green mussel Perna viridis, brown mussel Modiolus modulaides and charru mussel Mytella striigata were evaluated for thier biological activities. To extract the peptides, the enzymes trypsin, neutrase, alcalase and pepsin were used. From the resulting hydrolysates, partially purified fractions were then obtained using membrane filtration with a <10 kDa molecular weight cut off. Both hydrolysates and fractions were tested for their antioxidant, antihypertensive, antihypercholesterolemic and anti diabetic activities. Results revealed that both the hydrolysates and fractions exhibited bioactivities but higher activities were detected in the fractions containing low molecular weight peptides. Comparing the enzymes, highest activities were found in hydrolysates and fractions from 2% trypsin hydrolysis. The significant bioactivities may be attributed to the presence of hydrophobic amino acids as found in our previous report showing the presence of 18 essential amino acids in P. viridis and M. modulaides. Findings of this study indicates the potential of these hydrolysates and peptide fractions to be used for pharmaceutical and neutraceutical applications.

Keywords: bioactive peptide fractions, enzymatic hydrolysis, mussel species, biological activities

CHARACTERISTICS OF SKIPJACK TUNA (Katsuwonus pelamis) ROE-POWDER USING DIFFERENT DRYING METHODS

Thithi Phetchthumrongchai and Wanwimol Klaypradit^,*

Department of Fishery Products, Faculty of Fisheries, Kasetsart University,

Bangkok 10900, Thailand.

^*Corresponding author: ffiswak@ku.ac.th

This study aimed to investigate physical, chemical and functional properties of mature skipjack tuna (Katsuwonus pelamis) roe in powder form. Mature roe ( M) was dried to obtain powder using three methods including hot air drying ( M-HD) , vacuum drying ( M-VD) and freeze drying (M-FD). The obtained roe powders were determined for color value, amino acid profile, equivalent umami concentration (EUC), functional properties and protein pattern. M- FD provided higher lightness (L*) but lower redness (a*) and yellowness (b*) compared to M- HD and M-VD. The three most abundant amino acids found in all powders were glutamic acid, leucine, and aspartic acid in the range of 13.79-14.61, 8.20-8.42 and 8.16-8.39 g/100 g of protein, respectively. M-HD provided the EUC values (73.09 g monosodium glutamate/100 g of sample), which was significantly ( p ≤ 0.05) higher than those of M-VD and M-FD ( 57. 28 and 51.72 g monosodium glutamate/100 g of sample, respectively). The roe powders had protein solubility in the range of 13.42-21.80%. The foaming capacities of M-FD (121.78%) was high than those of M-VD and M-HD (104.89% and 102.67%, respectively), but their foam stabilities were not observed. The protein band at molecular weight of 97 kDa (vitelline) represented the major protein. Therefore, our study suggests the potential of dried tuna roe to be used as a protein source with increase taste reception.

Keywords: Skipjack tuna, tuna roe, roe powder, drying method, protein source

CHARACTERIZATION OF BIOACTIVE PEPTIDES WITH ANTIOXIDANT AND ANTIHYPERTENSIVE ACTIVITIES FROM FOUR SPECIES OF UNDERUTILIZED MARINE BIVALVES

Nicole Pauline P. Plagata, Ma. Lorena M. Serisola, Gleann P. Salido and Rhoda Mae C. Simora*

Institute of Fish Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo 5023 Philippines

*Corresponding author: rcsimora@up.edu.ph 

Marine bivalves are protein rich edible seafood and the high protein quality in these bivalves could indicate their potential as precursors for bioactive peptides. A proper hydrolysis technique at suitable and optimum conditions plays an important role in liberating the biofunctional activities of these peptides. This study evaluated the protein profile as well as the antioxidant and antihypertensive properties of four species of underutilized marine bivalves namely Placuna placenta, Placuna ephippium, Scapharca inaequivalvis, and Marcia hiantina using hot and cold aqueous extraction. Generally, cold water extracts gave higher total soluble protein yield as compared to samples under hot water, with the highest total soluble protein found in the cold water extract of P. placenta at 21.37%. Low molecular weight proteins (<10.5-14 kDa) were found also in the cold water extracts of M. hiantina and S. inaequivalvis as revealed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). Moreover, cold water extract of M. hiantina demonstrated highest DPPH (2,2-diphenyl-l-picrylhydrazyl) radical scavenging activity and ferric-ion reducing capacity (76.24% and 1.58 mol Trolox equiv/mL sample, respectively), while cold water extract of P. ephippium exhibited the highest ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity (93.67%). For the antihypertensive activity, hot water extract of P. placenta demonstrated the highest ACE (angiotensin-I converting enzyme) inhibitory activity at 91%. These results suggest that the four bivalve species might possess bioactive peptides eliciting antioxidant and antihypertensive activities. It also confirmed the potential of using aqueous extraction to liberate the peptides, which is a cost-effective method in lieu of the high cost of chemical and enzymatic hydrolysis. Further investigations intending to purify these active compound(s) should be considered to clarify their chemical nature.

Keywords: marine bivalves, aqueous extraction, low molecular weight peptides, antioxidant, antihypertensive

CHARACTERIZATION OF THE ANTIMICROBIAL PROPERTIES OF LACTIC ACID BACTERIA FROM SALT-FERMENTED YELLOWFIN TUNA (THUNNUS ALBACARES) ENTRAILS (“DAYOK”)

Brittany Miroslava O. Briton^1*, Encarnacion Emilia S. Yap¹

¹Institute of Fish Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines, ²Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

*Corresponding author: bobriton@up.edu.ph

Fish fermentation is a traditional processing method utilizing indigenous raw materials that enable the production of diverse microbial multifunctional resources with antimicrobial properties. In this study, lactic acid bacteria (LAB) from salt-fermented entrails from yellowfin tuna (Thunnus albacares), locally known as dayok in the Philippines were prepared using different salt concentration (10%, 17.5%, and 25% ). The presumptive LAB were isolated and subsequently analyzed. Preliminary screening of the isolates revealed 10 catalase-negative and Gram-positive isolates, 6 catalase-positive and Gram-positive isolates, 1 catalase-positive and Gram-positive isolate, and 1 catalase-negative and Gram-negative isolate. Results also showed high total viable count (TVC) of the control samples (T0) during the fermentation period. Overall, a decreasing TVC per treatment was also observed with increasing salt concentration across. The potential of the isolates to inhibit the growth of undesired microorganisms was evaluated periodically during the fermentation process. Test on antagonism revealed that 11 of the presumptive LAB isolates showed antagonistic activity against pathogenic bacteria groups (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa). However, only one isolate displayed strong inhibition, particularly against an indicator strain (B. subtillis). For the test for antibiotic resistance, all 10 isolates showed resistance against chloramphenicol. The highest degree of antibiotic susceptibility was to erythromycin with a zone of inhibition of 34 mm while the lowest was to cephalexin with an inhibition zone of 6 mm. This study further revealed that 17.5% salt concentration enabled the production of LAB with the most potential in terms of its antimicrobial properties. Overall, this study provides an insight on the potential of presumptive LAB species in dayok to exhibit antimicrobial properties and the resistance profile of such species against several antibiotics.

Keywords: dayok, lactic acid bacteria, bacterial characterization, antimicrobial activity

COMPARATIVE STUDIES ON THE PHYSICAL AND CHEMICAL PROPERTIES OF PROTEIN POWDER PREPARED FROM SKIPJACK TUNA (KATSUWONUS PELAMIS) LIVER USING HEAT TREATMENT AND SUPERCRITICAL FLUID EXTRACTION

Chanita Jeerakul¹, Lalitphan Kitsanayanyong¹, Wanwimol Klaypradit ¹ and Pramvadee Tepwong^1,*

¹Department of Fishery Products, Faculty of Fisheries, Kasetsart University, Thailand.

^*Corresponding author: ffispdt@ku.ac.th

This study aimed to develop protein powder from Skipjack tuna (Katsuwonus pelamis) liver (TL), a solid byproduct of the tuna canning industry, for utilization as a source of protein. Heat treatment (H) at different temperatures and supercritical carbon dioxide fluid extraction (SC-CO2) at different pressures followed by freeze-drying were applied, and the physical and chemical properties of the tuna liver protein powders (TLPPs) were evaluated. H at 85 °C (H85) and SC-CO2 at 350 bars (SC-CO2-350) resulted in the remarkably highest total protein content among the preparation conditions. The maximum extraction yield, total protein content, and protein recovery yield of TLPP obtained with SC-CO2-350 were 74.02%, 71.75%, and 99.38%, respectively, while those obtained with H85 were 73.46%, 53.81%, and 82.44%, respectively. The m content of TLPPs obtained from SC-CO2-350 and H85 was reduced by 90.23% and 22.12%, respectively, when compared to TL powder. Both TLPPs produced in this study contained all of the essential amino acids (EAAs) and met the FAO's recommendations for adults. The top three prominent EAAs among treatments were leucine, lysine, and valine. The lightness (L*) and yellowness (b*) values of TLPPs were improved (61.35-62.15 and 20.59-24.71, respectively), while the redness (a*) value was decreased (6.79- 7.99), compared to that of the TL powder. Furthermore, the moisture content and water activity of both TLPPs were within the standard range for powdered and low-moisture foods. The results obtained in the present study suggest the potency of SC-CO2-350 as an effective method to produce TLPP with high protein, low lipid, and high nutritional values, which could be further used as an alternative protein ingredient.

Keywords: Tuna liver, Protein powder, Byproducts utilization, Functional ingredient, Heat treatment, Supercritical carbon dioxide fluid extraction

DETERMINE THE FACTORS INFLUENCING VIETNAMESE CONSUMPTION OF TRACEABLE FISHERIES FOOD: A CASE STUDY IN HO CHI MINH CITY

Tien D. Mai^1*, My H. Cao¹, Thom N. Ta¹

¹Faculty of Fisheries- Nong Lam University, Vietnam

*Corresponding author and email: tien.maidang@hcmuaf.edu.vn

Food contamination and food poisoning have been causing serious problems undermining Vietnamese consumers' confidence, and traceable food is a potential solution. This study aimed to determine the factors affecting the intention to utilize traceable fisheries food, and the impact level of each factor on consumers in Ho Chi Minh City through the "Theory of Planned Behavior" (TPB). The Structural Equation Modeling (SEM) method was utilized to analyze the data of 200 participants who were surveyed through face-to-face interviews at organic food stores, supermarkets, shopping centers, and some other locations in Ho Chi Minh City. Research results proved that customers’ intention for the consumption of traceable fisheries products is formed mainly based on their attitudes, while subjective norms demonstrated an indirect effect on intention through attitude. Although the prediction of intention on traceable fisheries consumption behavior was indicated, perceived behavioral control was the key to actual consumption.

Keywords: food choice, fisheries consumption, theory of planned behavior (TPB), traceable food

EFFECT OF SOY PROTEIN CONCENTRATE, MODIFIED STARCH AND TEMPERATURE ON PHYSICO-CHEMICAL PROPERTIES OF TUNA DARK MUSCLE PROTEIN ISOLATE GEL

Bach T. Nguyen^1,*, Bao Nguyen¹, Son T. Do¹, Bao N. D. Huynh¹, Trung S. Trang¹

¹Nha Trang University, 02 Nguyen Dinh Chieu Street, Nha Trang City, Khanh Hoa Province, Viet Nam

^*Corresponding author: ntbachnt@ntu.edu.vn

This study investigates the effect of co-gelling agents such as modified starch (MS) and soy protein concentrate (SPC) on penetration force, weight-loss ratio, size-shrinkage, change of TBARS and TVB-N of fresh tuna dark muscle fish protein isolate (TDMFPI) gels were stored at (4°C ± 1). The results showed that when adding ingredients (MS, SPC) at a ratio of 4-6%, the state of the TDMFPI gel was improved, the rate of weight loss and size shrinkage of protein gels after heating decreased about 6 times. Penetration force, shear strength and the rate of weight loss of protein gels did not increase much after 7 days of storage at (4^oC ± 1). TBARS and TVB-N (gel adding MS) indexes did not increase significantly during the storage time of less than 5 days. But TVB-N index increased significantly after 3 days on storage for gels adding SPC.

Keywords: Fish protein isolate, Gel, Penetration force, Shear strength, Tuna dark muscle, Weight-loss

EFFECTS OF PRE-TREATMENT ON ANTIOXIDANT CAPACITY OF GAC (Momordica cochinchinesis Spreng) PULP EXTRACT FOR FISH OIL PRESERVATION

Dao L.A. Nguyen^1*, Duyen T.K. Huynh¹, Thịnh Q. Nguyen¹, Ha T.N. Nguyen¹, Phu M. Tran¹, Kazufumi Osako², Toshiaki Ohshima²

¹Can Tho University, Xuan Khanh Ward, Ninh Kieu District, Can Tho City, Viet Nam

²Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Japan

^*Corresponding author: nladao@ctu.edu.vn

The aim of this study was to investigate the effect of pre-treatment on antioxidant activity of Gac (Momordica cochinchinesis Spreng) pulp extract which could be applied in fish oil preservation. Gac pulp was pre-treated by soaking in ascorbic acid solution whereas the control was untreated sample. Then, ethanolic extraction was conducted for both samples to obtain crude extracts. Gac pulp extracts were investigated the antioxidant activity through evaluating the capacity of elimination free radical DPPH and the total phenolic compounds presented in the extracts. The antioxidative effeciency of Gac pulp extract added in marine fish oil and salmon oil at 60°C was assessed by measuring peroxide value (PV) and Thiobarbituric acid reactive substances (TBARS). Results showed that the extract which was treated in ascorbic acid solution had higher ability to eliminate free radical DPPH (IC₅₀ = 2,29 mg/mL) and total phenolic compounds (0,9±0,004 mgGAE/g) compared to the control. Gac pulp extract pre-treated in ascorbic acid displayed the potential application of in storage of salmon oil and marine fish oil.

Keywords: Ascorbic acid, fish oil preservation, Gac pulp, Momordica cochinchinesis Spreng, pre-treatment.

EFFECTS ON AGAR QUALITY OF POST-HARVEST IMMERSION OF Gracilariopsis heteroclada AT DIFFERENT HYPERSALINE CONDITIONS 

Leonilo F. Endoma, Jr.^1*, Duke R. Monsale¹, Iris Ann G. Borlongan², Pearl Aljean Santacera³, Encarnacion Emilia S. Yap¹

¹Institute of Fish Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

²Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

³Institute of Marine Fisheries and Oceanology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

* Corresponding author: lfendoma@up.edu.ph 

This study evaluated the effects of post-harvest hypersaline immersion on agar extracted from Gracilariopsis heteroclada. Samples were treated at different salinity levels: 20, 30, 40, 50, 60 practical salinity unit (PSU) in ambient-type 20-L concrete tanks for 14 days. Agar powder and gel extracted from dried seaweeds were then tested for physico-chemical analyses. Results in this study found significant effect of post-harvest immersion at hypersaline conditions on agar gel strength, whiteness, and yield among agar extracts. Samples at 40 PSU produced gels with significantly good rheological properties (p<0.05): gel strength at 390.61 g•cm^-2, breaking strength at 3.01 N, and cohesion at 0.64 cm. Though results showed that 40 PSU had significantly better rheological properties as compared to other samples, 50 PSU exhibited the best potential to be utilized based on significantly higher yield (about two times more than other samples, p<0.05), and FTIR results showing high absorbance at 1.19 wavenumber 930 cm^-1 indicating high 3,6-anhydrogalactose concentration. At 0.01 level of significance, positive significant correlation was found between gel strength with cohesion, rigidity, L* (agar gel lightness), b* (agar gel yellowness), WI (agar gel whiteness index), and SI (agar gel saturation index). The 40 PSU sample had the highest L* (agar gel), and WI (agar gel) at 47.79, and 47.76, respectively, among the experimental samples. And samples of 50 PSU had the highest b* (agar gel), and saturation index at 2.55 and 3.02 respectively (p<0.05). Albeit, the low gel strength compared to industrial standards, the high lightness and whiteness values of samples could prove useful to the commercial value of G. heteroclada agar as food additives.

Keywords: Agar Extraction, Hypersaline Condition, Gel Strength, Practical Salinity Unit (PSU), Whiteness

Authors: Mookdaporn Kiettiolarn, Lalitphan Kitsanayanyong, Jirawan Maneerote, Sasimanas Unajak, Pramvadee Tepwong*

Authors: Karmelie Jane M. Monaya, Honey Lyn R. Gomez, Lhumen A. Tejano*, Jose P. Peralta

NUTRITIONAL COMPOSITION AND CONSUMER PREFERENCE OF RESTRUCTURED TUNA FILLET TREATED WITH LIQUID SMOKE

Sahubawa L*¹, Zafira T.F.¹

¹Departement of Fisheries, Faculty of Agriculture, Gadjah Mada University Flora Street No. 01, Bulaksumur UGM Campus, Yogyakarta-Indonesia, 55281

* Corresponding author: lsahubawa@ugm.ac.id

Tuna flakes are leftover meat on the bones and heads of tuna that can be used for processing various commercial products, including restructuring products and analogues. The aim of the study was to determine the effect of the concentration of liquid smoke and soaking time on the quality and consumer preference for ready-to-eat restructured tuna filets and to get the best treatment to improve the quality of the filets. The study used a completely randomized design with 2 factors as the source of treatment, namely “liquid smoke concentration” with 2 (two) treatments (3% and 4%) and soaking time with 2 (two) treatments (15 minutes and 30 minutes). The quality parameters tested were water content, ash, protein, fat, carbohydrates, total volatile base-nitrogen (TVB-N), and bacteria total plate number (NPT-bacteria). The attributes tested in the analysis of consumer preferences are appearance, aroma, taste, and texture. The water content of restructured tuna filet ranged from 54.47 – 57.14%, ash content (2.29 – 2.68%), protein content (26.67 – 28.16%), fat content (0.51 – 0.94%) and carbohydrate content (13.25 – 15.47%). Commercial smoked tuna steak was preferred by panelists compared to liquid smoked restructuring filet. Based on TVB-N and ALT analysis, it turned out that the quality of liquid smoked tuna restructuring tuna filets was still acceptable until the 7th day under cold storage conditions (4˚C).

Keywords: tuna flakes, liquid smoke, concentration, soaking, restructured fillet, quality

OPTIMIZATION ENZYME CONCENTRATION AND FLAVOURZYME ADDITION TIME FOR THE PRODUCTION OF ENZYMATIC PROTEIN HYDROLYSIS FROM SNAKEHEAD HEAD BY USING ENZYME ALCALASE AND FLAVOURZYME

Thu T.M. Truong ^{1, 2*}, Thuy T.M. Le ², Muoi V. Nguyen³, Truc T. Tran³

¹PhD student of Food Technology Course 2020, Can Tho University, Campus II, 3/2 Street, Ninh Kieu District, Can Tho City, Viet Nam

²College of Aquaculture and Fisheries, Can Tho University, Campus II, 3/2 Street, Ninh Kieu District, Can Tho City, Viet Nam

³College of Agriculture, Can Tho University, Campus II, 3/2 street, Ninh Kieu District, Can Tho City, Viet Nam

^*Corresponding author: ttmthu@ctu.edu.vn 

The study was conducted to investigate enzyme concentration and flavourzyme addition time to produce protein hydrolysate from snakehead (Channa striata) head by adding method alcalase before and flavourzyme after. Hydrolysis process was performed by using response surface method with 4 factors including alcalase concentration (23.18 - 56.81 U/g protein); flavourzyme concentration (69.54 - 170.45 U/g protein); flavourzyme addition time (6.95 - 17.04 hours) and hydrolyzing time (19.91 – 40.09 hours) included 19 treatments and 3 replicates. The results showed that the optimal hydrolysis conditions for snakehead head were alcalase concentration (53.1 U/g), flavourzyme concentration (104.1 U/g), flavourzyme addition time (7.93 hours) and hydrolysis time (31.1 hours). With optimal hydrolysis condition gave high degree of hydrolysis (53.3%), protein recovery (66.0%) and amino acid content (14.3 g/L).

Keywords: Alcalase, flavourzyme, flavourzyme addition time, optimization, snakehead head

OPTIMIZATION OF MICROPLASTICS (MPS) EXTRACTION FOR PHILIPPINE SARDINES (SARDINELLA SPP.)

Rowelyn M. Sargadillos¹, Leonilo F. Endoma, Jr¹., Mae Grace G. Nillos², Encarnacion Emilia S. Yap¹

¹Institute of Fish Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao 5023, Iloilo, Philippines, ²Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao 5023, Iloilo, Philippines

*Corresponding author: esyap@up.edu.ph

Plastic pollution is not just a significant environmental concern but also a health and food safety issue. There are a variety of analytical methods developed to isolate MPs from biotic matrices. However, there have been reports that various methods could potentially damage and underestimate MP polymers during analysis. In addition, the detection of MP contamination also presents a challenge particularly for particles that measure <0.1mm. The information, therefore, on optimized chemical digestion and detection methods for the increased MP recovery rate and better extraction efficiency are crucial. In this study, different temperature, and time combinations for alkaline digestion (using 10% KOH) using sardine muscle tissues were tested to quantitatively determine the optimum conditions for better digestion efficacy and efficiency, polymer recovery, and reagent effect. Results revealed that digestion at 60°C for 16h provided satisfactory digestion efficiency, efficacy, and polymer recovery. This study also tested different staining concentration of Nile red to acetone (3ug/mL, 5ug/mL, and 10ug/mL concentrations) to qualitatively determine the optimum concentration based on the changes of the tested polymer FTIR spectra and the recovered polymer counts. Results showed that staining solution of 10ug/mL did not significantly change the FTIR spectra of the tested polymers and was proven to be the only staining concentration that produced a fluorescent image of the tested polymers. In summary, results from this study showed a time and cost effective and efficient protocol in digesting the biological matrix, with less impact on the integrity of the tested polymers, namely polyethylene terephthalate (PET), polystyrene (PS), and polypropylene (PP).

Keywords: Microplastics, plastic pollution, polymer, food safety, Sardinella spp.

OPTIMIZATION OF PROTEIN HYDROLYSIS OF YELLOWFIN TUNA (Thunnus albacares) VISCERA PROCESSING WASTES USING TRYPSIN

Leonilo F. Endoma, Jr.*, Richelle L. Potato, Raymund B. Parcon, Sharon N. Nuñal

Institute of Fish Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

* Corresponding author: lfendoma@up.edu.ph 

Enzymatic hydrolysis of yellowfin tuna viscera (YFTV) at varying trypsin concentration, hydrolysis temperature and time combinations were investigated. Response Surface Methodology (RSM) using DesignExpert® was designed to determine the optimum conditions to yield high soluble protein content (mg/mL), and degree of hydrolysis (DH, %). Bradford protein dye-binding and o-phthaldial-dehyde (OPA) methods were used to measure the responses which were used to establish a mathematical model. Results in this study showed that at 0.5 mg trypsin concentration at 40 °C for 3.6 h, significantly highest soluble protein content (1.59 mg/mL), and DH (70.90%) was obtained (p<0.05). Optimum conditions were found at 0.5780 mg trypsin concentration at 60°C for 2.4 h yielding the highest desirability value of 0.9730. Optimization of the combined conditions show that when enzyme substrate ratio is minimized, time is minimized and temperature is maximized, the desirability of DH and protein is 1 and the combined Desirability Value close to 1. Results in this study can be used in designing conditions for the hydrolysis of tuna wastes to yield higher protein content and higher degree of hydrolysis.

Keywords: Trypsin Enzymatic Hydrolysis, Tuna Processing Wastes, Soluble Protein, Degree of Hydrolysis, DOE

OPTIMIZATION OF THE ENZYMATIC HYDROLYSIS OF YELLOWFIN TUNA, Thunnus albacares VISCERA BY RESPONSE SURFACE METHODOLOGY

Mary Famille Don De Asis, Sharon N. Nuñal*, Leonilo F. Endoma Jr

Institute of Fish Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visaya, Miagao, Iloilo, Philippines

*Corresponding author: snnunal@up.edu.ph

Tuna is abundant in the Philippines but the by-products during its processing to various forms may be a source of waste and environmental pollution. To minimize these wastes, they are utilized directly or fermented to serve as food for humans and animals as well as a functional food ingredient since they are rich in proteins and polyunsaturated lipids. For this purpose, they are often converted into protein hydrolysates using proteolytic enzymes. This study optimized the enzymatic hydrolysis of Yellowfin tuna (Thunnus albacares) viscera to produce hydrolysates with a high degree of hydrolysis and foaming capacity using Response Surface Methodology (RSM) with the enzyme Neutrase at various concentrations (0.5, 1.0, and 1.5 % w/v) and hydrolysis time of 60 to 180 minutes. From the RSM generated model, the optimum conditions to obtain the highest degree of hydrolysis are 179.50 min and 1.5 % enzyme concentration. For the highest foaming capacity, the optimum conditions are 176.58 hydrolysis time and an enzyme concentration of 1.5 %. The predicted optimum values using the generated linear and quadratic equations are 17.26 % degree of hydrolysis and 1.60 % foaming capacity, respectively.  The lack of a fit test for both responses yielded an insignificant value (p > 0.05) for the model, suggesting that the regression coefficient was sufficient for estimating both responses under any group of variables respectively. Therefore, the optimized conditions of the yellowfin tuna viscera could be used in food production systems. The utilization of tuna viscera as protein hydrolysates could make a significant contribution to the waste management of these fish by-products.

Keywords: Yellowfin tuna viscera, Protein hydrolysate, Response Surface Methodology, Degree of Hydrolysis, Foaming Capacity

PREPARATION, CHARACTERIZATION AND APPLICATION OF PVA/HPMC/ROSELLE ANTHOCYANIN ACTIVE PACKAGING FOR SHRIMP PRESERVATION

Jiayin Huang^1.2, Zhiheng Hu^1,2, Gaoshang Li^1,2, Lingping Hu^1,2, Yaqin Hu^2*

¹Institute of Food Engineering, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, Zhejiang, China, 310058

²College of Food Science and Engineering, Hainan Tropical Ocean University; Marine Food Engineering Technology Research Center of Hainan Province; Collaborative Innovation Center of Marine Food Deep Processing, Sanya, Hainan, China, 572022

^*Corresponding author: 1004346262@qq.com

With the development of society, biodegradable active packaging is considered to be a promising choice for food preservation. In this study, the PVA/HPMC/roselle anthocyanin (PHR) active film was prepared, the interaction behavior contained in film matrix as well as the preservation mechanism on shrimp freshness was investigated. Firstly, the structural characterizations revealed that roselle anthocyanin was firmly immobilized into PVA/HPMC matrix by generation of hydrogen bonds. Then, with the increasing of anthocyanin contents, the PHR film exhibited better mechanical, barrier, antioxidant and antibactieral properties. However, the hydrophobic properties decreased significantly due to the strong hydrophilicity of roselle anthocyanin. Furthermore, the preservation behaviors of PHR film on Penaeus vannamei were studied. The results demonstrated that the PHR film could effectively extend shrimp shelf-life and enhance sensory attributes. Meanwhile, the PHR film was also able to modify shrimp texture by rearrangement of water distribution and stabilization of protein conformation. Overall, the PHR film with excellent physical and functional characteristics was considered to be a novel active food packaging.

Keywords: Active packaging, Penaeus vannamei, Food preservation, Roselle anthocyanin

PROPERTIES OF TUNA BLOOD POWDER PREPARED FROM FREEZE DRYING AND VACUUM DRYING

Mantira Hawangjoo and Wanwimol Klaypradit*

Department of Fishery Products, Faculty of Fisheries, Kasetsart University, Bangkok 10900, Thailand

*Corresponding author: ffiswak@ku.ac.th

The study aimed to determine properties of tuna blood powder prepared from different drying methods. The fresh tuna blood was obtained from a canned tuna processing. The blood was analyzed for microbiological and chemical properties that the microbiological property of tuna blood was under the standard level of fresh fishery products and protein content was found at 14.39% (w/w). The tuna blood was dried by different two drying methods including freeze drying at -20⁰C for 24 hr and vacuum drying at 80^oC together with 72 mbar for 28 ± 2 hr. The obtained tuna blood powder was determined for amino acid profile, mineral and vitamin content. The results showed that all powder contained all essential amino acids and the main three amino acids for the powder from freeze drying and vacuum drying were aspartic acid, glutamic acid and leucine, which were found at 66.86, 66.07, 59.27 mg/g of sample and 70.31, 65.24, 62.88 mg/g of sample, respectively. Iron and zinc content were found for 102.10, 16.00 mg/100g and 116.50, 13.70 mg/100g, respectively. Vitamin A was detected at 0.39 mg/100g and 0.07 mg/100g, respectively but vitamin B was not detected. This study suggests the way how to increase the utilization of tuna blood waste as a potential source of amino acids and minerals.

Keywords: Tuna blood, canned tuna processing, freeze drying, vacuum drying

QUALITY CHANGES  OF PICKED OYSTER (Crassostrea gigas) SAUCE DURING STORAGE TIME

Huyen Thi Tran^1*, Quyen Le Vu¹, Viet Tran Nu Thanh Bui¹, Giang Thanh Tran¹, Duong Thi Hoai Ngo², Hai Thi Minh Pham²

¹Falcuty of Food Technology, Nha Trang University, No 2 Nguyen Dinh Chieu Street, Nha Trang city, Viet Nam

²Institute for Biotechnology and Enviroment - Nha Trang University, No 2 Nguyen Dinh Chieu Street, Nha Trang city, Viet Nam

Corresponding author: huyentt@ntu.edu.vn

Changes in sensory, chemical and microbiological qualities of pickled oyster sauce, processed by traditional Vietnamese pickling method, pasteurized after bottling, during storage at room temperature of 26 °C - 30 °C for 16 weeks was studied. The longer storage time, the lower sensory score of the product but the quality is still quite good (according to the scoring method of TCVN 3215-79), the pH of the product reduced from 4.5 to 4.2, moisture content of the product had no significant changes, around 62%; the total nitrogen content decreased significantly at the first 5 weeks of storage then lessened slightly and stabilized during the 14^th,15^th, and 16^th weeks. Nitrogen content of NH₃ in the product was low (0.1g/100g) at week 0, but decreased very slightly in the following weeks, while the amino acid nitrogen content increased rapidly during the first 5 weeks of storage and then kept raising slightly up to week 15 before decreasing at week 16. During this storage period, E. coli, Staphylococcus aureus, Salmonella, Vibrio parahaemolyticus in the product were not detected; Coliforms, Clostridium perfringens and yeasts and molds counts were lower than the allowable limit that according to the regulations on maximum limit of biological contamination in food of the Ministry of Health of Vietnam (46/2007/QD-BYT). Particularly, the total aerobic bacteria increased from 14^th week  and exceeded the allowable limit in this regulation by 16^th week. Thus, this pickled oyster sauce product that processed by traditional Vietnamese methods could have a shelf life of 15 weeks in room temperature storage conditions.

Key words: pickled oyster sauce, qualities of pickled oyster

REDUCING OF CONTAMINATED HEAVY METALS IN SARDINE BY USING ACETIC ACID SOLUTIONS

Janthira Kaewsrithong*, Arisara Pratakkarn, Supadee Dangkongrod, Patiparn Choodum

Fishery Technology and Innovation, Faculty of Science and Technology, Prince of Songkla University, Pattani campus, Thailand

*Corresponding author: janthira.k@psu.ac.th

Sardine is an important raw material for not only human canned food industries but also pet foods. However, the contamination of heavy metals in sardine from various sources has been reported. Reducing of contaminated heavy metals was investigated by soaking or boiling sardine samples in 0-3% acetic acid solutions. Then sample weighing and sensory evaluation by 5-points-hedonic scale were conducted. Heavy metals in sardine were analyzed by inductively coupled plasma mass spectrophotometer. Acetic acid solutions used in this study could reduce contaminated As, Hg and Pb in sardine. In addition, these solutions could increase weight of fish. Nevertheless, acetic acid solution showed effects on appearance, color, odor, taste and texture of samples but within acceptable scores.

Keywords: reduce, heavy metal, contaminate, sardines

THE EFFECTS OF OZONATED SLURRY ICE TREATMENT ON MICROBIAL, PHYSICOCHEMICAL, AND QUALITY OF LARGE YELLOW CROAKER (Pseudosciaena crocea) DURING COLD-CHAIN CIRCULATION

Xuening Chen¹, Weiqing Lan^{1,2,3, *}, Yanan Zhao¹, Jing Xie^{1,2,3, *}

¹College of Food Science and Technology, Shanghai Ocean University, Shanghai City, China

²Shanghai Aquatic Products Processing and Storage Engineering Technology Research Center, Shanghai City, China

³National Experimental Teaching Demonstration Center for Food Science and Engineering (Shanghai Ocean University), Shanghai City, China

*Corresponding author: wqlan@shou.edu.cn, jxie@shou.edu.cn       

Freshness is an important attribute in the quality classification of aquatic products and is of concern to retailers and consumers. The purpose of research is to evaluate the effects of different ice treatment on the microbial, physicochemical and quality characteristics of large yellow croaker (Pseudosciaena crocea) during cold-chain circulation. Different ice treatment methods (flake ice (FI), slurry ice (SI) and ozonated slurry ice (OSI)) were used during circulation, respectively. Changes in microorganisms (total viable count (TVC), psychrophilic bacteria count (PBC), sulfuretted hydrogen -producing bacteria count, pseudomonas bacteria count), physicochemical (pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), K-value, biogenic amines (BAs), color difference, texture profile analysis (TPA)), which also combined with low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) were measured to evaluate the feasibility preservation methods. The results showed that the quality of large yellow croaker was significantly improved with OSI treatment. OSI could reduce the TBA, TVB-N, K-value and BAs by inhibiting the growth of microorganisms. The changes of texture and color verified the combination ozone and slurry ice could get more successful effect during circulation. The LF-NMR and MRI analysis suggested that OSI samples got a better effect on the reduction of water loss. Compared with FI, the OSI treatment could retard the water migration and extend shelf-life for another 6 days. Taken together, the combination of slurry ice and ozone could maintain better quality of large yellow croaker. Therefore, OSI will be a promising long-term preservation method for maintaining the quality of large yellow croaker. However, considering the complexity environment in fish and organoleptic properties of aquatic products, further studies including safety and stability experiments, dosage optimization and effects on the sensory properties of aquatic products are necessary before being used in aquatic products.

Key words: Pseudosciaena crocea; Circulation; Slurry ice; Ozone; Quality; Shelf-life

SENSORY AND PHYSICO-CHEMICAL ANALYSIS OF SMOKED HAMONADO AND DRIED HAMONADO SARDINES (Sardinella lemuru)

Vaye Melbourne T. Tirado, May Flor S. Muegue*, Ernestina M. Peralta, Ariel S. Sefil, Sheina B. Logronio

Institute of Fisheries Processing Technology, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo 5023

*Corresponding author: msmuegue@up.edu.ph

Philippines is producing abundant Sardinella lemuru during peak season and processing initiatives for this fish species remain limited. This study developed novel products using the species, the smoked hamonado and the dried hamonado sardines. Sensory profiling, consumer acceptability testing, and physico-chemical analyses (proximate analysis and salt content determination assay) of the developed products were conducted. Results showed that there is a significant difference in the proximate composition, product profiling, and consumer acceptability of smoked hamonado sardine and dried hamonado sardine. Storage study of the products at chilled condition (0-3°C) was also conducted for four weeks. The microbiological (TPC), physico- chemical (TBARS and Aw), and sensory parameters of the products were monitored weekly during storage. The TPC and the malondialdehyde levels were slower in smoked hamonado sardine (3.1 × 102 - 5.9 × 10² CFU/g and 0.24-0.3 mg MDA) than dried hamonado sardine (3.9 × 104 - 1.8 × 10⁶ CFU/g and 1.88-4.03 mg MDA) on the last day of storage study. Results from sensory evaluation, water activity, Thiobarbituric acid- reactive substances test (TBARS), and total plate count (TPC) indicate that the product continuously deteriorates as storage time progresses but both products remained acceptable in terms of sensory attributes after the four-week storage study. Both the smoked hamonado sardine and hamonado sardine obtained positive consumer acceptance.

Keywords: Sardinella lemuru, sensory profiling, storage study, Thiobarbituric acid test (TBARS), total plate count (TPC)

ABUNDANCE OF BILLFISH BY-CATCH AND ITS SIZE VARIATION IN THE EAST COAST OF PENINSULAR MALAYSIA

Mohamed Shahrul Daniel Hamzah ¹, Rashidah Abdul Razak ^1,2, Juliana Mohamed ^1,2, Muhammad Zahir Ramli ^1,2, Muhammad Faiz Pa’suya ³, Rahimi Abdul Rahman ⁴,

Fikriah Faudzi ^1,2, Aimimuliani Adam ^1,2,*

1. Department of Marine Science, Kulliyyah of Science, International Islamic University Malaysia, 25200 Kuantan Pahang
2. Institute of Oceanography and Maritime Studies (INOCEM), International Islamic University Malaysia, Cherok Paloh, Pahang

3 Pusat Pengajian Sains Ukur dan Geomatik, Univerisiti Teknologi Mara (Perlis), Kampus Arau, 02600 Arau, Perlis.

4. Department of Construction Management, Universiti Malaysia Pahang, Pahang.

^*Corresponding author: aimiadam@iium.edu.my

In Malaysia, billfish is typically not the fisheries primary targets but well recognized in sport fishing. Rompin, Pahang is known for the migration route’s pitstop for billfish, and this migration contribute to the expansion of the local economy by creating vital coastal livelihoods and recreational opportunities. Unfortunately, the drastic reduction of billfish catches since past five years urge for the investigation. Thus this study was carried out to determine the abundance and size variation of the billfish by-catch along the East Coast of Peninsular Malaysia. Samples of billfish were collected at fish landing jetty in Kuantan, Pahang from April 2021 to July 2022. All billfishes collected were identified as Indo-Pacific Sailfish (Istiophorus platypterus) and no other species was observed. Monthly abundance showed that there was an increasing trend from early to middle of the year and suddenly decreased. This trend can be observed in both years of 2021 and 2022. This fluctuated trend was coincided with the catches experienced by the anglers in Rompin waters (from personal conversation). Studies on billfish abundance in Pacific Ocean region showed similar trend and this was linked to the spawning activities which was expected to occur from April to November. With regards to the size composition, monthly variation in size composition showed that large size of sailfish can be observed in 2022 while the smaller size of sailfish was observed in 2022. This size composition indicated that the sailfish found in Pahang waters were composed of juvenile and adult fish (early adult and recently-spawned adult). All these sailfishes were assumed to be in their migration journey from northernly waters (China, Taiwan, and Japan) toward southernly waters (Australia) and stop by along Pahang waters for nursery and feeding. 

Keywords: Billfish, Istiophorus platypterus, diet composition, fishery, conservation