Fish Protein Isolate Research Articles

Effect of the addition of fish protein isolate on biscuits’ physicochemical and sensory properties

Biscuits are among the most popular baked goods. However, traditional biscuits are frequently poor in protein and low in the content of the essential amino acids. Meanwhile, fish protein isolate (FPI) is proven to contain all the essential amino acids. The addition of FPI to biscuits can improve their nutritional value but may change their physicochemical and sensory properties. The present study was, therefore, conducted to investigate the effect of the addition of different levels of FPI prepared from trimmings of yellowfin tuna on the physicochemical properties and sensory acceptability of biscuits. The results showed that the moisture and water activity of biscuits with 1.6-5.4% FPI added significantly decreased compared with the control biscuits without FPI. The hardness of the biscuits with FPI added compared to the control biscuits, however, was not significantly different. The results of the sensory evaluation also showed that the appearance, texture, color, aroma, taste, mouthfeel, and overall acceptability of the biscuits with FPI added and the control biscuits did not differ significantly, except for the color and aroma of the biscuits with 3.8-5.4% FPI added. The addition of 2.7% FPI to biscuits was found to have no negative impact on the biscuits’ quality. These findings suggest that FPI prepared from the trimmings of yellowfin tuna is a potential protein source that can be used to improve the nutritional value of biscuits. Keywords: Protein-enriched biscuit, Thunnus albacares, fish protein isolate, value-added products, malnutrition

Nutrification and fat reduction of deep-fried protein isolates

Deep-fried (DF) foods are considered nutritionally-inferior due to increased fat content, although they are popular with consumers due to desirable sensory characteristics. This study attempted to reduce fat of DF surimi, DF fish-protein-isolate (FPI), and DF chicken-protein-isolate (CPI) by pre-baking or pre-roasting. Surimi, FPI, and CPI were also nutrified with ω-3-rich oil, fiber, and KCl-based salt substitute. Pre-baking decreased (p < 0.05) fat content, while pre-roasting increased (p < 0.05) it. Pre-baking resulted in less (p < 0.05) changes to cook loss, moisture loss, expressible moisture, water-holding-capacity, whiteness, and texture when compared to pre-roasting. Pre-baking also better maintained ω-3 PUFAs concentration than pre-roasting, resulting in higher (p < 0.05) concentration of α-linolenic (ALA, 18:3ω3), eicosapentaenoic (EPA, 20:5ω3), and docosahexaenoic (DHA, 22:6ω3) FAs as well as unsaturated FAs and total ω-3 FAs in DF surimi, DF FPI, and DF CPI. Pre-baking in combination with nutrification using ω-3 PUFAs improved nutritional value of DF foods, while causing minimal quality changes.

Enrichment of pasta with Pangasianodon hypophthalmus protein isolate for improved sustainability, nutrition, and quality

SummaryThe study was conducted to formulate pasta with fish protein isolate (FPI) (0%, 2.5%, 5.0%, 7.5%, and 10.0%) and assessed its functional, cooking, textural, proximate, FTIR, and sensory attributes in comparison to control. Results showed that addition of FPI significantly influenced the functional properties. The protein (12.25%–20.79%) and ash (0.40%–3.21%) content increased significantly (P &lt; 0.05), while cooking time, swelling index, and cooked weight decreased. The supplementation also increases the firmness (0.181–0.440 kg) and toughness (0.680–1.33 kg/s) of pasta. FTIR spectra show the presence of the amide I, II, and III groups, with peaks at 1636, 1542, and 1228 cm−1 with increased intensity as concentration increases. Pasta (uncooked and cooked) exhibits decrease in whiteness and increase in yellowness and redness with increased FPI levels. Pasta with 5% FPI was found acceptable by the panellists with an acceptable fish odour and highest overall acceptability scores.

A Preliminary Study on the Use of Protein Isolate Produced From Trout in Tarhana Soup

The aim of this study is to use protein isolate that produced from fillet trout by pH shifting (acid) processes, in tarhana soup as protein enrichment. Three different soup groups were prepared; control (C): without isolate; 3.5% protein isolate added (T1) and 7% protein isolate added (T2). For sensory characteristics of soups, groups were compared by using color and sensory analysis by panelists. According to the sensory analysis results, the highest texture, odor and general acceptability values (7.38; 7.50 and 7.50, respectively) were reported in T1 while, these values were the lowest in C (6.50, 7.13 and 7.13, in order). When the results were evaluated in general, it was determined that there was no significant difference in terms of general acceptability in both isolate-added soup groups compared to the C. Test score of T1 is higher than T2 in terms of texture, it was determined that the isolate added groups were better than the C. With this preliminary study, it was determined that the fish protein isolate did not have a negative effect on the sensory properties of tarhana. More research is needed to establish the impact of additional fish protein isolate on the functional and biochemical quality of tarhana.

Preparation and Characterization of Fish Protein Isolate from Tiger Tooth Croaker (Otholithus ruber) Obtained through PH Shift Method

Development of Fish Protein Isolate (FPI) from tiger tooth croaker (Otholithus ruber) fish meat using the pH shift method was carried out during this study. Tiger tooth croaker was used as raw material because of their abundance and comparatively low price. During the study, the physical characteristics and proximate composition of the fresh fish were analysed. The average length of fish was 19.95 cm and weighed 94.6 g. respectively. FPI treated at different pH treatments (2.5, 4, 7, 11.5 and 12.5) were analyzed for proximate composition, peroxide value and functional characteristics. In the present work, Tiger tooth croaker (Otolithes ruber) fish was found to be suitable for fish protein isolate production using acid or alkali processing and isoelectric precipitation. During storage at ambient temperature for 120 days in a 200 gauge LDPE pouch, Fish Protein Isolates treated at different pH treatments (2.5, 4, 7, 11.5 and 12.5) indicated an increase in moisture content, reduction in protein and lipid content and no significant reduction in ash content. The total protein content was specifically high for pH 7 followed by pH 12.5, 11.5, 4 and 2.5. The effect of different pH on PV of fish protein isolates showed increasing content with increasing storage. The functional properties such as water-holding capacity (WHC), oil-holding capacity (OHC), emulsifying capacity (EC) and foam measurements (Foaming capacity (FC) and foam stability (FS) exhibit high values for all the samples of fish protein isolates. The quality attribute of functional properties of all fish protein isolates samples showed a trend of decreasing during the storage of 120 days.

Utilization of fish protein isolates to supplement oat-based cookies and assessment of end product quality.

Bullseye and Pacu fish processing waste were valorized through its conversion into functional protein isolates, followed by the utilization of recovered proteins to supplement oat-based cookies at different levels (0, 2, 4, 6, 8 and 10g/100g) and baking temperatures (100, 150, 170, 180, 190 ˚C). With different replacement ratios and baking temperatures, the best selection was made at (4 and 6%) and baking temperatures (160 and 170 ˚C) for BPI (Bullseye protein isolate) and PPI (Pacu protein isolate) based cookies, respectively based on sensory and textural characteristics. The developed products were analyzed for its nutritional, physical, textural, and sensory quality. No significant differences were found in the moisture and ash contents of the cookies from different lots, while the protein content was highest for cookies with 6% PPI. The spread ratio was lower reported for the control cookies compared to the fish protein isolate-based counterpart (p < 0.05), and it decreased with increasing thickness of cookies. Significantly higher total essential amino acid values were obtained in cookies supplemented with 6% Pacu protein isolates, whereas 4% Bullseye protein isolate-supplemented cookies were higher in total non-essential amino acid content. The total plate count was higher in control cookies (0.35 ± 0.33cfu/g) compared to fish protein isolate-supplemented cookies. The hardness values were maximum for control group cookies (19.14 ± 0.98 N) compared to protein isolate incorporated cookies (17.22 ± 1.05 N and 16.26 ± 0.9 N). However, the difference among the all-treatment group is not significant (p > 0.05).

The Effect of Probiotic Biscuit on Faecal Microbiota in Malnourished Children

A human intervention study on the effect of 90 days supplementation of creamed biscuit with the potential of containing probiotic strain E. faecium IS-27526 at a dose of 108cfu/day on Bifidobacterium in the faecal microbiota of malnourished children under 5 years was conducted. The study was a Randomized Double Blind Placebo Controlled Trial for children under five years old. There were 5 groups with 6 children each: P0 = control biscuit with control cream; P1 = fish and soy protein isolate biscuit with control cream; P2 = control biscuit with probiotic cream; P3 = fish and soy protein isolate biscuit with probiotic cream (every day) and P4 = fish and soy protein isolate biscuit with probiotic cream (every two days). PCR was used to detect Bifidobacterium and Enterococcus faecium in faeces samples. It was concluded after 90 days of supplementation, only 25% of children in the controlled group (P0) harboured Bifidobacterium. In treated groups P1 and P4, the percentage of children positive for Bifidobacterium was approximately 60%, while in groups P2 and P3 the prevalence was 100%. However, the increase of 10% was only demonstrated by P3 as 100% of Bifidobacterium content has been shown in group P2 at the pre-treatment condition. In the controlled group (P0), E. faecium could not be identified either pre or post-intervention, in contrast to the treated groups which showed an increase in some treatments with the highest of 66.7% (group P3). No adverse effect was observed during 90 days of supplementation to children. In conclusion, supplementation of fish and soy protein isolate biscuit and/or probiotic cream every day at a dose of 108cfu/day is considered safe for children under five years old and even increased the number of samples with the presence of bifidobacteria and E. faecium in the fecal microbiota.

Protein Characteristics and Bioactivity of Fish Protein Hydrolysates from Tra Catfish (Pangasius hypophthalmus) Side Stream Isolates.

Enzymatic hydrolysis is a novel method to recover highly potent bioactive fish protein hydrolysates (FPHs) from fish processing side-streams. The common way of producing FPHs directly from fish side-streams may be inappropriate due to the excess of lipids and pro-oxidants, especially in lipid-rich streams, as obtained from Tra catfish. This study aimed to optimise the hydrolysis conditions for a commercial enzyme (Alcalase® 2.4 L) (enzyme concentrate, temperature, and time) in FPH production from the fish protein isolate obtained from Tra catfish dark muscle (DM-FPI) using the pH-shift method. The degree of hydrolysis (DH), protein recovery (PR), and antioxidant properties, including DPPH radical scavenging activity (DPPH-RSA) and total reducing power capacity (TRPC), were measured to evaluate the effects of the hydrolysis conditions on the FPHs. Optimal hydrolysis was obtained at an enzyme/substrate protein ratio of 3% (v/w) and a hydrolysis temperature of 50 °C for 3 h. The FPHs obtained from different substrates, including DM-FPI, abdominal cut-off (ACO) FPI, and head and backbone blend (HBB) FPI, had similar DHs under these optimum conditions, ranging from 22.5% to 24.0%. However, the FPH obtained from abdominal cut-off isolate (ACO-FPH) showed the highest PR of 81.5 ± 4.3% and the highest antioxidant properties, with a DPPH-RSA of 86.1 ± 1.6% and a TRPC of 6.4 ± 0.4 equivalent mg vitamin C/g protein. The resulting FPHs present a natural source of antioxidants with great potential for food applications, especially the ACO-FPH. In addition, all FPHs had excellent amino acid profiles, indicating strong potential for their use as supplements. Tra catfish protein-rich side-streams can thus be processed into high-value bioactive FPHs using Alcalase for human consumption.

Using aquatic raw materials in the technology of flour culinary and confectionery products

Common flour products as a part of a human diet have been observed. Using aquatic raw materials has been advised to solve these problems. In addition to using cod liver oil and inactivated yeast cells, fish protein isolate is advised to use in the technology of bakery and flour culinary products. The recipe of such products has been optimized (optimal dosage of FPI is 5 % of dry weight to the flour quantity); the flow diagram is given. Wakame algae has been used in the technology of the confectionery product – biscuit dessert. It was added to the confiture layer as well as raspberry and sugar. The ratios of these ingredients have been optimized using experimental design method. The optimized recipe of the biscuit dessert has been developed.

Utilization of pangas protein isolates and by‐products in fish sausages: Effect on quality attributes and acceptability

Aim of the study was to aid the utilization of pangas protein isolates (PPI) and pangas processing by-products (PPB) in food products (rohu mince sausage) and to evaluate the quality of the developed products. Rohu mince in sausages was replaced with PPI and PPB at 0, 2.5, 5.0, and 10% levels and the composition, physical, textural, and sensorial quality of sausages were assessed. Increasing PPI and PPB content in sausages increased its crude protein and lipid content (p < .05); however, the expressible moisture of sausages decreased with increasing levels of PPI (p < .05). Increasing PPB and PPI content in sausages showed a negative impact on its gel strength, while the differences in the color, textural, sensory attributes and acceptability of sausages were insignificant. Results indicated that the PPI and PPB from pangas could be successfully incorporated into fish sausages without significantly affecting the quality and acceptability. Novelty impact statement In this study, pangas fish processing by-products (PPB) and protein isolates (PPI) were used to supplement fish sausages with an aim of its utilization in food systems. Adding PPB and PPI to sausages influenced its physicochemical attributes without significantly causing changes in its eating quality, opening a new way to utilize these raw materials in food industry. Using PPI and PPB, edible fish meat sausages with good acceptability could be developed.

Characterization of tuna dark muscle protein isolate

Fish protein isolate (FPI) was extracted from tuna dark muscle (TDM) using the pH-shift method that improves significantly its sensory quality and nutritional value. The amino-acid composition of the FPI was close to that of TDM, but the total protein content was higher. The solubility of FPI in water was higher than 85% at pH ≥ 6 and pH ≤ 3, but it dropped to about 10% at pH values close to the isoelectric point pI ≈ 5.0. The soluble FPI was present in the form of aggregates that were characterized by light-scattering. The microstructure of FPI solutions on larger length scales was probed by confocal microscopy, large protein flocs formed at pH close to pI. SDS-PAGE indicated that a significant fraction of myosin heavy chains was broken down into smaller chains. The viscosity decreased with decreasing of pH, which correlated with the decreasing size of the aggregates. Novelty Impact Statement Tuna dark muscle (TDM) represents a significant fraction of industrially processed tuna and it is currently considered a low value by-product because of its poor sensory qualities, but TDM has a high protein content that does not suffer from sensory defects if it is extracted by dispersing TDM at pH 12 and precipitating the dissolved protein at pH 5.5. The protein isolate is highly soluble (> 85%) in water at pH > 6 and pH < 3, where it is present in the form of small aggregates with average radii between 90 and 250 nm, depending on the pH. The characterization of the composition of TDM protein isolate and its properties in water show that it is a viable product for use in industrial applications.

Physicochemical and Sensory Properties of Protein Isolate from Anchovy (Stolephorus insularis)

Anchovy is one of the primary fishery commodities in Indonesia; however its development as fishery products is currently suboptimal. Due to its high protein content, anchovy is potential to be developed as a source of value-added fish protein isolate. This study aims to produce anchovy protein isolate (API) and evaluate its physical, chemical, and sensory properties. The API was prepared from defatted anchovy flour. Isolation of anchovy protein was carried out using a pH-shifting method. The API was then analyzed for its physicochemical (bulk density, color, proximate) and sensory properties. The results showed that anchovy protein was more soluble at pH 11 and less at pH 5. Yield and protein recovery of API were 26.39 and 36.86% wb, respectively. The API had 92.20% protein, 3.64% moisture, 2.18% ash, 2.26% lipid, and 3.36% carbohydrate content on a dry basis. The results showed that the API exhibited good physical and sensory properties such as bulk density, color, the best score on sweetness, seaweed, bitterness, off-flavor, aroma, and rancid taste. There was no significant difference in sweet taste, off-flavor, aroma, and rancid taste between API and soy protein isolate (SPI) (p0.05). Overall, API demonstrated satisfactory nutritional properties and potential use as food ingredients.

Protein Recovery of Tra Catfish (Pangasius hypophthalmus) Protein-Rich Side Streams by the pH-Shift Method.

Increasing protein demand has led to growing attention being given to the full utilization of proteins from side streams in industrial fish processing. In this study, proteins were recovered from three protein-rich side streams during Tra catfish (Pangasius hypophthalamus) processing (dark muscle; head-backbone; and abdominal cut-offs) by an optimized pH-shift process. Physicochemical characteristics of the resulting fish protein isolates (FPIs) were compared to industrial surimi from the same raw material batch. The pH had a significant influence on protein extraction, while extraction time and the ratio of the extraction solution to raw material had little effect on the protein and dry matter recoveries. Optimal protein extraction conditions were obtained at pH 12, a solvent to raw material ratio of 8, and an extraction duration of 150 min. The resulting FPI contained <10% of the fat and <15% of the ash of the raw material, while the FPI protein recovery was 83.0–88.9%, including a good amino acid profile. All FPIs had significantly higher protein content and lower lipid content than the surimi, indicating the high efficiency of using the pH-shift method to recover proteins from industrial Tra catfish side streams. The FPI made from abdominal cut-offs had high whiteness, increasing its potential for the development of a high-value product.

Manufacture of Toman Fish Protein (Channa micropeltes) Isolate with Different pH Methods using Star Fruit (Averrhoa bilimbi) Acid

Toman fish (Channa micropeltes) is a type of freshwater fish that belongs to the genus Channa which is the largest size compared to the others and has high protein. This study aims to obtain the isolate of toman fish protein (Channa micropeltes) by the method of pH regulation using star fruit acid. Wuluh star fruit acid is used as a substitute for HCl in making fish protein isolates to reduce pH. This research method uses a Completely Randomized Design (CRD). The treatments consisted of (P1 = pH 4, P2 = pH 5, P3 = pH 6). The results showed that star fruit acid can replace HCl as a protein precipitant and P1 (pH 4) obtained the most isolates, namely an average protein content of 91.64% (db), a moisture content of 1.67%, ash content of 2.06 % (db), fat content of 2.74% (db), yield of 88.46%, and total amino acid composition of 61.30%, where the type of amino acid that dominates is glutamic acid (12.30%). Glutamic acid amino acid is the one that influences a lot in giving pH isoelectric point, in the treatment of P1 with pH 4 making isolates of toman fish protein to be the best treatment, because glutamic acid has an isoelectric point of 3.22 which is the closest to pH 4 plus also the pH of isoelectric point from other amino acids.

Utilization of protein isolates from rohu (Labeo rohita) processing waste through incorporation into fish sausages; quality evaluation of the resultant paste and end product.

Fish processing waste could be valorized by recuperating the nutrients for human consumption. Employing a suitable process would address the pollution problems associated with its dumping and would contribute to food security. In this study, protein isolates obtained from rohu (Labeo rohita) processing waste through the pH shift process (pH 13.0) were valorized through incorporation into pangasius (Pangasius pangasius) mince sausages (0.0, 50, 100, 250, and 500 g kg-1 ). These sausages were analyzed for their proximate composition, and their physical and eating quality. Increasing the isolate content (11.57% to 16.14%) in sausages increased their protein content and whiteness values (P < 0.05). At 250 g kg-1 level, the cooking yield was maximum, and the expressible fluid content of paste was minimum. Moreover, adding rohu protein isolates in pangasius mince increased the expressible moisture and decreased its folding and gel strength values (P < 0.05). The gel strength values were highest for the sausages without isolates (2648.67 g cm). In contrast, in the sausages containing 250, 100, and 500 g kg-1 isolate, the values were determined to be 847.88, 731.21, and 611.06 g cm, respectively. Replacing pangasius mince with rohu protein isolates had a non-significant effect on the sensory attributes of the sausages. Replacing pangasius mince with rohu protein isolates at 250 g kg-1 resulted in superior quality sausages compared with other levels tested. Incorporating rohu protein isolates in fish sausages improved the nutritional value without significantly reducing their eating quality. The findings of this study indicate promising potential for developing nutrient-rich foods using fish protein isolates. © 2021 Society of Chemical Industry.

Biochemical, microbial, and textural quality changes in rohu protein isolates supplemented pangas mince sausages packed in LDPE and cellulose casing during frozen storage

Influence of rohu protein isolate (25 g 100 g−1/ 25RPI) and casing material (LDPE and cellulose) on frozen storage (−18 ℃) characteristics of fish sausages was studied for a period of 3 months. Expressible fluid content of sausage emulsion increased as time of storage progressed to 3 months, reaching 31.32 and 27.11 g 100 g−1 for control and 25RPI, respectively. Water-holding capacity and cooking yield values showed a significant (p < .05) reduction, while the G′ and G″ values decreased, indicating the change in protein structure and gelling ability. Sausages packed in LDPE casings had higher oxidation and bacterial counts than sausages in cellulose casings. The sensory scores varied non-significantly in all the sausages during initial phase. After 3 months, sausages from COCL and 25RICL were still acceptable with sensory scores of 5.6 and 6.0, respectively (p < .05), indicating the better quality of sausages in cellulose than in LDPE casings. Novelty impact statement In this study, it was found that fish protein isolates could be successfully used to supplement fish sausages. Adding rohu fish protein isolates to sausages improved its nutritional profile and did not cause significant differences in its sensory attributes and acceptability, indicating the future possibilities of developing food products enriched with fish protein isolates. Among the two different casings tested, cellulose based casings were found to be promising due to its low cost, easy handling, and tight emulsion packing ability.

Microencapsulation of Anchovy Fish Oil (Engraulis encrasicolus) with Fish Protein (Equulites klunzingeri) Isolate: Nutritional Assessment

Fish protein isolates extracted from underutilised fish species were used for coating material of anchovy oils and their nutritive value was investigated in this study. For this purpose, Klunzinger’s ponyfish (Equulites klunzingeri) proteins were extracted by using pH shifting process. Micro particles were prepared with anchovy oil (Engraulis encrasicolus) as core material (10%), and as wall materials a ratio of 5% and 10% fish protein isolate (FPI) was used. Maltodextrin (DE: 18:20) was added to both groups in a ratio of 10%. The emulsions were fed immediately into a Buchi Mini Spray Dryer (B290, Switzerland). The inlet temperatures, feed rate and aspiration rate were maintained at 160 oC, 15 mL/min and 35m3/h, respectively. The lipid, protein and moisture contents of anchovy oil microcapsules containing 5% FPI and 10% FPI were found as 43.76-43.09%, 4.34- 9.82% and 3.95-3.92%, respectively. The main amino acids in microcapsule samples were lysine, glutamic acid, and leucine which constituted in the range of 349-578 mg/100 g sample for microcapsules containing 5% FPI, and 805-1547 mg/100 g sample for microcapsules containing 10% FPI. In addition to that, essential and non-essential amino acids (E/NE) ratio for microencapsulated fish oil with 5% FPI and 10% FPI were determined 0.92 and 0.95, respectively. As a result of this study, it can be concluded that the addition of fish protein isolate enhanced the nutritive value of microencapsulated fish oil.

Selar (Selar crumenophthalmus) Fish Protein Hydrolysate Has Antidiabetic Properties Possibly through GLP-1

Background : Enzymatic hydrolysis of fish protein using protease or fish protein hydrolysate can form bioactive peptides that have antidiabetic activity. One potential mechanism of fish protein hydrolysate is reducing blood glucose through increased endogenous glucagon like peptide (GLP)-1 production. Tempeh is soy fermented food that has protease which is potential biocatalyst in producing fish protein hydrolysate. Objective: To evaluate the antidiabetic properties of Selar (Selar crumenophthalmus) fish protein hydrolysate using tempeh protease as biocatalyst and duodenal gene expression of GLP-1. Methods: Selar fish protein isolate was digested for 8 hours at 37°C using crude tempeh protease. Diabetes mellitus was induced in rats by intraperitoneal injection of streptozotosin (65 mg/kg bw) and nicotinamide (230 mg/kg bw). Fish protein isolate and hydrolysate in dose of 300 mg/bw and 500 mg/ bw were orally administered daily for 4 weeks. Blood was drawn for fasting serum glucose and lipid profile analysis. Total RNAs were isolated from duodenum and quantitative real time PCR was performed to quantify mRNA expression of GLP-1. Data were analyzed using one way ANOVA and gene expression analysis were performed using Livak. Results and Discussion: There is a significant difference on fasting serum glucose, total cholesterol, triglyceride, LDL-cholesterol, HDL-cholesterol and duodenal GLP-1 mRNA expression level between groups (p&lt;0.05). The duodenal GLP-1 mRNA expression was the highest in rats who received hydrolyzed fish protein 500 mg/ bw. Conclusion: Hydrolysis of selar fish protein using tempeh protease has anti-diabetic properties possibly through GLP-1 production.

Characteristics of sausages affected by reduction and partial substitution of pork backfat with pre-emulsified soybean oil

AbstractImprovement of nutritive profile of pork sausages was performed by fat reduction and partial substitution of backfat with soybean oil (SBO). The control sausage was made from pork backfat. For the studied samples, SBO in native and pre-emulsified forms was used for partial substitution of backfat at 25% (by wt of backfat) to produce sausages with various fat contents (30, 20, and 10%). Discontinuity of protein matrix could be observed with increasing fat content, especially for addition of pork backfat. Improvement on product stability could be achieved using SBO, especially pre-emulsified form, to partially replace animal fat. Better dispersibility of the SBO droplets through the meat matrix compared to backfat globules was suggested by the greater continuity in the microstructure of the sausages with SBO. For the sausages supplemented with pre-emulsified SBO, the non-meat protein used as emulsifier could further strengthen the protein network, thereby resulting in enhanced product stability and retained textural attributes of the sausages. The fish protein isolate presently employed as emulsifier to prepare SBO emulsion could be promisingly used to produce more nutritive sausages by providing adequate stability.

Utilisation of isoelectric precipitation to recover fish protein isolate from seafood processing waste

Threadfin bream (Nemipterus japonicus) is an important marine fish species used in the preparation of surimi. The waste generated from surimi production contains large quantity of recoverable proteins, which could be utilised for byproduct development. In this study, Isoelectric precipitation (IEP) technique as a method to recover proteins from fish processing waste was attempted. The alkali aided IEP process extracted the fish protein isolate (FPI) efficiently with a yield of 84.13±0.11%. The highest protein yield was recorded at a homogenised sample to water ratio of 1:9. Maximum protein content was found at pH 13 with 19.63 ±0.52% yield. FPI extracted had higher protein content, less ash and low lipid contents compared to the fish processing waste. The mean yield and protein composition of FPI extracted atdifferent treatments of pH and sample to water ratiowere found to be significantly different (p&lt;0.05). Sample to water ratio of 1:9 and pH 13 was found to be the best combination among the different treatments attempted for FPI extraction from threadfin bream processing waste.