Utilizing Bullseye fish processing frame waste to produce edible proteins and quality assessment of the recovered proteins

The aim of the study was to utilize the waste generated from Bullseye (Priacanthus hamrur) fish processing to recuperate proteins. Considering the cost-effectiveness, versatility, and color improvement after the pH shift method, proteins from this waste were extracted by the pH shift method using hydrochloric acid and sodium hydroxide. The properties of extracted proteins were studied in detail. During the protein solubility measurement, maximum solubilization was found at pH 3.0 (13.10 mg/mL) on the acidic side and pH 11.0 (14.25 mg/mL) on the alkaline side with a total yield of 51.62 ± 0.23 and 45.42 ± 0.29 (%), respectively. The process variables tested in this study showed a significant effect on protein solubility (p < 0.05). The protein content of the isolates extracted from the waste was 23.80 ± 0.49 and 22.48 ± 0.39% for acid and alkali processed isolates, which was significantly higher than the mince (19.46 ± 0.67%). pH shift processing of Bullseye proteins caused a significant reduction in its pigments, lipids, and myoglobin content (p < 0.05). Proteins extracted using alkali had significantly higher values for foaming stability, water holding capacity, and emulsion capacity than proteins extracted using acid. An overall assessment indicated that protein isolates obtained using alkali extraction were better in terms of textural attributes, gelling ability, and amino acid profile than protein isolates extracted using the acid process.

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 10 g/100 g) 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 ± 0.33 cfu/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).

Blue agave inulin-soluble dietary fiber: effect on technological quality properties of pangasius mince emulsion-type sausage

BACKGROUND

The aim of the work was to investigate the influence of supplementing pangasius mince-based emulsion sausages with blue agave-derived inulin at 1% (T1), 2% (T2), 3% (T3), 4% (T4), and 5% (T5) on its technological quality attributes and acceptability.

RESULTS

The cooking yield of T-2, T-3, and T-4 sausages (96-97%) exhibited no significant difference (P > 0.05), which was higher than the other lots. The T-2 batter exhibited a significant difference with all other treatments, showing the lowest total expressible fluid (12.20%) value, indicating the highest emulsion stability of the batter. There was a significant effect on the diameter reduction of the cooked sausages as the level of inulin increased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the proteolysis of raw mince without inulin and new bands in cooked sausage samples were observed. Increasing inulin content increased the hardness of the sausages from 2510.81 ± 114.31 g to 3415.54 ± 75.88. The differential scanning calorimetry melting temperatures of peak 2 of the T-1, T-2, T-3, and T-4 increased as the inulin content increased from 1 to 4%. The scanning electron microscope images exhibited a smooth appearance on the surface as the inulin level increased.

CONCLUSION

The sausages incorporated with the 2% and 3% blue agave plant-derived inulin (T-2 and T-3) showed better sensory overall acceptability scores than the control. The results suggested that the blue agave plant-derived inulin could be efficiently utilized at the 2% and 3% levels to enhance the quality of emulsion-type pangasius sausage. © 2023 Society of Chemical Industry.

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

BACKGROUND

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.

RESULTS

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.

CONCLUSION

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.

Influence of processing and pH on amino acid profile, morphology, electrophoretic pattern, bioactive potential and functional characteristics of alfalfa protein isolates

Protein isolates were prepared from wet heat processed (APIp) and unprocessed alfalfa seeds (APIc) and characterized for composition and functionality at different pH. APIc and APIp exhibited high content of all the essential amino acids. Antinutrient content of APIp was lower in comparison to APIc and marked reduction in the trypsin inhibitor (85.97%) and lectin activity (100%) was observed. Processing did not cause much reduction of bioactive constituents and antioxidant activity of APIp. Alfalfa protein isolates exhibited complex polypeptide banding ranging from molecular weight of 11-75 kDa. APIp exhibited change in the conformation of protein discerned as alteration in interrelated nuances of ATR-FTIR spectra, XRD-pattern, morphology, charge on proteins and reduced solubility in comparison to APIc due to processing. APIp exhibited marked improvement in the functional properties in comparison to APIc discerned as improved hydration, surface active and gelation properties. Highest hydration and surface active properties were exhibited at pH 9.0, even though APIp at pH 7.0 showed fairly similar functional properties as APIc and APIp at pH 9.0. APIp exhibited reduced least gelation concentration in comparison to APIc at pH 7.0 and also engendered gelation at pH 4.0 and 9.0 contrary to APIc.

Effect of organic acid on recovery yields and characteristics of rohu (Labeo rohita) protein isolates extracted using pH shift processing

BACKGROUND

Proteins recovery using hydrochloric acid (HCl) in acid-aided solubilization could cause greater loss in its functionality over alkali-aided solubilization. Moreover, using HCl in edible foods is also a health concern. Replacing HCl with organic acids for acid-aided solubilization could address these problems. The aim was to study the effect of organic acid (glacial acetic acid) as a replacement for HCl during pH shift processing on the characteristics and functionality of rohu (Labeo rohita) protein isolates. Rohu proteins were obtained by solubilizing at pH 3.0 and pH 11.0 using glacial acetic acid and sodium hydroxide (10 mol L^-1 ).

RESULTS

Results showed that solubilization at pH 11.0 gave higher protein yields (766.8 ± 2.4 g kg^-1 ) compared to solubilization at pH 3.0 (735.7 ± 7.1 g kg^-1 ) (P < 0.05). Isolates from acid-aided solubilization had higher whiteness and total pigment content over isolates obtained by alkali-aided solubilization. Rohu isolates recovered by alkaline solubilization showed higher water and oil holding capacity, gel strength, folding scores, foaming and emulsion capacity than acid processed isolates (P < 0.05). Solubilization of rohu proteins using glacial acetic acid produced isolates with low breaking force (149.0 g), low storage modulus (G') values and low folding test score (1.0) over the alkaline isolates (P < 0.05).

CONCLUSION

Results indicated that, recovering rohu proteins using organic acid (glacial acetic acid) could produce isolates with poor functional properties, while using the organic acid to precipitate the proteins solubilized by alkali-aided processing could produce proteins with better yields and functionality. © 2019 Society of Chemical Industry.

Utilization of freshwater mussel (Lamellidens marginalis) for the isolation of proteins through pH shift processing: characterization of isolates

Study was conducted to use underutilized freshwater mussel (Lamellidens marginalis) for the recovery of proteins using pH shift method and to study the functionality and characteristics of the recovered isolates. From the pH range tested (pH 2.0-13.0), maximum protein yields were obtained during solubilization at pH 2.0 and pH 13.0 (p < 0.05). During the protein recovery process, pH 13.0 was found to have minimal effect on proteins resulting in higher protein yields compared to pH 2.0. Isolates obtained by both acidic and alkaline solubilization processes had low stability and poor gel network. Total lipid content, total myoglobin, and pigment contents were reduced significantly (p < 0.05) during pH shift processing, resulting in whiter protein isolates and protein gels. All the essential amino acids were present in the isolates recovered by acid and alkaline solubilization, indicating the complete recovery of amino acids. No microbial counts were observed in any of the isolates prepared using acid and alkaline-aided processing. Acid and alkaline solubilization (pH shift) process was found to be promising for the recovery of proteins from underutilized freshwater mussel thus by reducing the supply demand gap.

Acid and alkaline solubilization (pH shift) process: a better approach for the utilization of fish processing waste and by-products

Several technologies and methods have been developed over the years to address the environmental pollution and nutritional losses associated with the dumping of fish processing waste and low-cost fish and by-products. Despite the continuous efforts put in this field, none of the developed technologies was successful in addressing the issues due to various technical problems. To solve the problems associated with the fish processing waste and low-value fish and by-products, a process called pH shift/acid and alkaline solubilization process was developed. In this process, proteins are first solubilized using acid and alkali followed by precipitating them at their isoelectric pH to recover functional and stable protein isolates from underutilized fish species and by-products. Many studies were conducted using pH shift process to recover proteins from fish and fish by-products and found to be most successful in recovering proteins with increased yields than conventional surimi (three cycle washing) process and with good functional properties. In this paper, problems associated with conventional processing, advantages and principle of pH shift processing, effect of pH shift process on the quality and storage stability of recovered isolates, applications protein isolates, etc. are discussed in detail for better understanding.

Recovery and characterization of proteins from pangas (Pangasius pangasius) processing waste obtained through pH shift processing

Study was conducted to recover proteins from pangas (Pangasius pangasius) processing waste (fillet frames) using pH shift method and to characterize the recovered isolates. pH 2.0 from acidic range and pH 13.0 from alkaline range were found to have maximum protein recovery (p < 0.05). During the recovery process, acidic pH (pH 2.0) was found to have minimal effect on proteins resulting in more stable isolates and strong protein gels. Alkaline pH (pH 13.0) caused protein denaturation resulting in less stable proteins and poor gel network. Both acidic and alkaline-aided processing caused significant (p < 0.05) reductions in total lipid, myoglobin, and pigment content thus by resulting in whiter protein isolates and gels. The content of total essential amino acids increased during pH shift processing, indicating the enrichment of essential amino acids. No microbial counts were detected in any of the isolates prepared using acid and alkaline extraction methods. pH shift processing was found to be promising in the utilization of fish processing waste for the recovery of functional proteins from pangas processing waste thus by reducing the supply demand gap as well pollution problems.

Quality changes in fresh rohu (Labeo rohita) cutlets added with fibers from ragi, oat and jowar

Purpose

This study aims to develop fiber-enriched cutlets from minced meat of rohu and study the effects of fiber inclusion on composition, cooking properties and acceptability of cutlets.

Design/methodology/approach

Cutlet mix prepared using rohu mince was divided into four lots, out of which three lots were enriched with fibers from ragi (RFC), jowar (JFC) and oat (OFC) at 10 per cent over and above its quantity. Prepared cutlets were analyzed for nutritional composition, texture, cooking properties and sensorial quality.

Findings

Moisture, protein, fat, fiber and ash contents (per cent) of the fiber-enriched cutlets ranged between 40.4-42.0, 24.5-25.5, 13.2-14.7, 1.8-2.0 and 2.4-2.5 per cent, respectively. The addition of fibers increased the cooking yield of cutlets from 84.6 to 87.5 per cent. RFC lot cutlets had the lowest whiteness values and the highest hardness and shear force values. Cutlets from all the lots had an overall acceptability scores more than 7.0, indicating the sensorial acceptability. Although the differences were insignificant, cutlets from the RFC lot were less acceptable, which might be because of the dark color and tough texture. Hence, jowar and oat flour at 10 per cent can be used to enrich rohu cutlets without affecting their sensorial acceptability.

Research limitations/implications

Sources of fiber will be the major limitation in the work, as the fiber inclusion may negatively affect the quality and acceptability of cutlets. Time of cooking will also influence the final product characteristics, which need to be standardized.

Practical implications

Fish is a rich source of protein but lacks fiber, which is essential for body metabolism. Grains are rich source of fibers but lack some essential nutrients required by the body. In India, many people are dependent on fish for protein due to its high nutritious value. So enriching fish meat with fiber sources will address the health-related problems associated with low-fiber diets. The methodology developed in this work can be used to fulfill the demand for balanced and nutritious diet. Because of increasing health awareness, fish products with added fiber will also increase its market potential.

Social implications

The methodology developed can be used by small-scale entrepreneurs to earn more income by developing functional fish products with low-cost ingredients. The developed products will not only address the issues related to the consumption of low-fiber diets but also create a market for fish products because of their health-benefiting effects.

Originality/value

The work is completely original in nature. The results reported are unique and the outcome of the research has social applicability.