Impact of antioxidant potential of rohu (Labeo rohita) swim bladder gelatin hydrolysate on oxidative stability, textural and sensory properties of fish sausage enriched with polyunsaturated fatty acids.

The impact of rohu swim bladder gelatin hydrolysate (SBGH) at different levels on textural, sensory, oxidative, and microbial properties of polyunsaturated fatty acids enriched rohu fish cooked sausages (PUFA-RFS) were investigated in the current study. SBGH addition enhanced the lightness values of PUFA-RFS compared to both control sausages (without SBGH and with butylated hydroxyanisole (BHA) (P > 0.05). PUFA-RFS added with 3% SBGH exhibited higher hardness, cohesiveness, and gumminess throughout the storage duration at both 4 °C and -20 °C temperatures when compared to other sausages counterparts. PUFA-RFS added with SBGH displayed lower PV, TBARS, and total microbial counts than the control sausages. Furthermore, PV, TBARS, and total microbial count values of sausage decreased with an increase in SBGH level, indicating retardation in lipid oxidation and microbial growth by SBGH in a dose-depended manner. Nevertheless, sausage added with 3% SBGH had higher overall acceptability than other sausage counterparts. Therefore, SBGH could retard lipid oxidation and improves textural properties of PUFA-enriched fish sausage.

Production of Antioxidant, Angiotensin-Converting Enzyme Inhibitory and Osteogenic Gelatin Hydrolysate from Labeo rohita Swim Bladder.

Optimization of antioxidants and angiotensin-converting enzyme (ACE) inhibitory potential gelatin hydrolysate production from Labeo rohita (rohu) swim bladder (SBGH) by alcalase using central composite design (CCD) of response surface methodology (RSM) was investigated. The maximum degree of hydrolysis (DH), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), total antioxidants (TAO), and ACE inhibitory activity were achieved at 0.1:1.0 (w/w) enzyme to substrate ratio, 61 °C hydrolysis temperature, and 94-min hydrolysis time. The resulting SBGH obtained at 19.92% DH exhibited the DPPH (24.28 µM TE/mg protein), ABTS (34.47 µM TE/mg protein), TAO (12.01 µg AAE/mg protein), and ACE inhibitory (4.91 µg/mg protein) activity. Furthermore, SBGH at 100 µg/ml displayed osteogenic property without any toxic effects on MC3T3-E1 cells. Besides, the protein content of rohu swim bladder gelatin (SBG) and SBGH was 93.68% and 94.98%, respectively. Both SBG and SBGH were rich in glycine, proline, glutamic acid, alanine, arginine, and hydroxyproline amino acids. Therefore, SBGH could be an effective nutraceutical in functional food development.

Preparation, purification, and identification of novel antioxidant peptides from red-bellied pacu (Piaractus brachypomus) fish meat protein hydrolysate.

The current study investigates the preparation, purification, and identification of novel antioxidant peptides from Piaractus brachypomus fish (RBPF) meat. Antioxidant peptides from RBPF meat protein hydrolysate (RPMPH) were fractionated by ultrafiltration (3 kDa MWCO membrane). RPMPH-IF (MW < 3 kDa) fraction displayed significantly higher antioxidant activities (P < 0.05) (DPPH, ABTS, FRAP, and Fe2+chelating activity). RPMPH-IF was purified by Sephadex G-25 gel filtration chromatography, and the RPMPH-1 fraction exhibited significantly higher antioxidant activities (P < 0.05). Subsequently, the RPMPH-1 fraction was purified by reversed-phase high-performance liquid chromatography. RPH-8 showed the highest antioxidant activities. The sequence of peptides of the RPH-8 fraction was later identified by LC-MS/MS and MASCOT software. RPH-8 fraction showed the two peptides with MW of 1105.52 Da and 748.25 Da, and the sequence of peptides was identified as His-Asn-Leu-Gly-Leu-Leu-His-Gly-Asp-Met and Asp-Ala-Pro-Ser-Met-Asn-Asp, respectively. Thus, RPMPH or purified antioxidant peptides produced by probiotic Bacillus strain could be a bio-functional ingredient in food and nutraceutical applications.

Utilization of lactobacillus fermented proteins from meat processing wastewaters as a dietary protein source in poultry feed.

The present study aimed to evaluate the impact of fermented meat processing wastewater protein hydrolysate (FWMPH) prepared by Pediococcus lolii fermentation as an alternative protein source on growth performance, serum biochemistry, and hematological parameters of broiler chicks. FWMPH exhibited antioxidant, anti-angiotensin converting enzyme (ACE), and antimicrobial properties. A total of 60 one-day-old Vencobb broiler chicks were divided into five dietary groups on day 8 and a feeding trial was performed for 48 days. Diets were prepared by replacing soya protein concentrate (SPC) at different levels of FWMPH as the protein source. These diets were denoted as SPSD (100% SPC), FMP-25 (25% FWMPH + 75% SPC), FMP-50 (50% FWMPH + 50% SPC), FMP-75 (75% FWMPH + 25% SPC), and FMP-100 (100% FWMPH). FMP-25 and FMP-100 diet group broiler chicks showed the highest and lowest feed consumption (P < 0.05), respectively. However, the highest body weight gain (1506.08 ± 52.52 g) was observed in FMP-75 diet-fed chicks (P < 0.05). Furthermore, FMP-75 chicks displayed better feed conversion ratio (1.96), feed efficiency ratio (0.51), and protein efficiency ratio (2.32) values than other diet group chicks (P < 0.05), implying that the FMP-75 diet had better effect on the broiler growth. Also, the FMP-75 diet chicks showed better hematological values, serum biochemical parameters revealed no negative effect upon FWMPH consumption, and no pathological signs were observed in the histopathological examination as compared to the SPSD diet group (P < 0.05). Hence, the results could be helpful in the application of FWMPH at 75% level in the poultry feed as a potential protein ingredient in the countries looking for local feed protein products as soya bean meal replacement.

Impact of different extraction conditions on yield, physicochemical and functional characteristics of gelatin from Labeo rohita swim bladder.

Influences of different extraction temperatures (50, 60, and 70 °C) and time (3, 6, and 9 h) on yield, physicochemical, and functional properties of gelatin from swim bladder (SBG) of rohu (Labeo rohita) were investigated. Gelatin extracted at 60 °C (G60-9 h), and 70 °C (G70-9 h) temperature for 9 h showed highest gelatin yield 54.91 g/100 g, protein (92.35 g/100 g), and hydroxyproline (77.50 mg/g) content (P < 0.05) compared to other counterparts. All extracted gelatin showed major protein components as α-, ß-, and γ-chain with slight changes in band intensity. FTIR spectra showed significant loss of molecular order of triple-helix as temperature and time increased. Furthermore, G60-9 h exhibited higher emulsion, foaming, and gel strength than G70-9 h, and G50-9 h, respectively (P < 0.05). Therefore, G60-9 h could be appropriate conditions for the extraction of SBG with better yield, physicochemical, and functional properties.

Malabar sole (Cynoglossus macrostomus) skin as promising source of type I acid and pepsin solubilized collagens with potential bioactivity.

Fish skin is one of the major non-edible by-products formed during fish processing. This investigation focused on the sustainable valorization of Malabar sole (MS) skin for collagen, which can be utilized as potential alternative of mammalian collagen. Acid and pepsin solubilized collagen (ASC and PSC) were successfully isolated from MS skin with a yield (%, dry weight basis) of 49.5 ± 0.6 and 67.6 ± 0.5, respectively. The isolated collagens were characterized by SDS-PAGE, UV-absorption, DSC, SEM, FTIR spectroscopy, etc., analysis. Both collagens were characterized as type I by SDS-PAGE and the well preserved triple helical structure by FTIR and UV absorption analysis. Denaturation temperature (°C) of the MS skin collagens confirmed by DSC analysis was 33.67 (ASC) and 33.38 (PSC). Both collagens showed high solubility in acidic pH and low NaCl level, and also exhibited a comparatively high degree of fibril-forming capacity. Antioxidant potential of the isolated collagens was confirmed by DPPH (31.4-34.6% at 1.5 mg) and peroxyl (64.6-68.3% at 0.3 mg) radical scavenging assays and observed a dose dependent manner activity. Overall, the results suggested the possibility of using the MS skin as a potential substitute source of realistic type I collagen and also help to reduce issues of fish processing discards. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s13197-021-04996-8).

Production of egg white hydrolysate by digestion with pineapple bromelain: optimization, evaluation and antioxidant activity study.

Chicken egg white is known to be an excellent source of good quality proteins to make hydrolysate with potential bioactive properties. Enzymatic digestion is a well-known method to produce protein hydrolysates; however, the type of enzyme determines the bioactive potential of the protein hydrolysates due to difference in their catalytic specificity. In this study, process optimization, production and evaluation of whole egg white protein hydrolysate (WEWPH) using pineapple bromelain through the Box-Behnken design were carried out. The design experiment (r 2 = 0.9557) displayed a significant (p < 0.01) effect of pH of egg white (9.0), hydrolysis time (24 h), and enzyme/substrate ratio (3.2 unit/g substrate) on hydrolysis and to form bioactive WEWPH. Antioxidant activity of the WEWPH was confirmed by DPPH radical scavenging assay. Gel filtration chromatography, SDS-PAGE and FTIR spectroscopy analysis of WEWPH revealed the digestion of egg white and the integrity of WEWPH in terms of secondary structure. The WEWPH exhibited strong scavenging activities of DPPH (EC50 = 238.3 µg/ml), ABTS ABTS (EC50 = 54.9 µg/ml), peroxyl (EC50 = 391.6 µg/ml) and superoxide radicals. The WEWPH also displayed reducing power and singlet oxygen quenching activity. These results reveal that the bioactive WEWPH could be a promising ingredient in health food and nutraceuticals. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05188-0.

Application of proteins from different meat processing wastewater streams as a dietary protein source in animal feed.

The present study aimed to investigate the protein quality indices of meat processing wastewaters protein hydrolysate (FWPH) obtained by Pediococcus lolii fermentation using a rat bioassay. Different diets namely, SD (100% casein), F50 (50% FWPH+50% casein), F75 (75% FWPH+25% casein), and F100 (100% FWPH) were formulated and fed to 28 days old albino male Wistar rats (6 rats each group). SD and F50 group rats showed higher feed and protein intake among all diet group rats (P < 0.05). However, the highest body weight gain (142.16 ± 2.84 g) was noticed in the rats fed with the F50 diet (P < 0.05). F50 group rats presented better feed conversion ratio (FCR), feed efficiency ratio (FER), and protein efficiency ratio (PER) values as compared to other diet group counterparts (P < 0.05). Furthermore, no differences in values of urine, haematological, and serum biochemical parameters were observed in SD and F50 group rats (P > 0.05). However, haematological and serum biochemical parameters were slightly elevated in F100 group rats. F50 group rats presented the higher superoxide dismutase (SOD) and catalase (CAT) activities among all the diet groups (P < 0.05). Relative organ weights, serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT), and alkaline phosphatase (ALP) activities of F50 group rats were found similar to SD rats. Histopathological examination revealed that no incidence of organ toxicity is attributed to the F50 diet. Overall, F50 group rats exhibited good growth and development with no adverse effects in biochemical, haematological, and histopathology parameters. Therefore, FWPH at the 50% level could be used as a potential dietary protein source in feed for better growth performance of the animal.

Optimisation of ultrasound-assisted enzymatic extraction conditions of umami compounds from fish by-products using the combination of fractional factorial design and central composite design.

In this work, ultrasound-assisted enzymatic extraction (UAEE) conditions of umami compounds from Labeo rohita head (LRH) was optimised using the combination of fractional factorial design (FFD) and central composite design (CCD). Six factors that can potentially influence the degree of hydrolysis (DH), equivalent umami concentration (EUC), and extraction yield (EY) of umami extract were screened through FFD. The three most significant variables were further optimised using the CCD. The developed models were successfully fitted to the experimental data and used to determine optimal extraction conditions. The optimum DH (22.73%), EUC (6.61 g MSG/100 g protein), and EY (76.34%) of umami extract were achieved with a liquid-solid ratio of 3 (v/w), ultrasonication time of 19.20 min and hydrolysis time of 140.45 min. Besides, UAEE umami extract exhibited higher DH, EUC, EY, and umami taste compared to that of the conventional enzymatic extraction (CEE).

Recovery, physicochemical and functional characteristics of proteins from different meat processing wastewater streams.

Recovery, physicochemical and functional characteristics of proteins recovered from different meat processing wastewater streams were revealed in the present study. Wastewaters from surimi processing (SPW) and slaughterhouses, namely fish (FSW), cattle (CSW), poultry (PSW), and goat (GSW), exhibited protein, fat, ash, moisture, and microbial load in the range of 1.28-7.04%, 0.86-2.34%, 0.02-0.80%, 89.81-97.44%, and 5.33-5.81 CFU/mL, respectively. Among the wastewaters, SPW presented slightly higher protein (7.04%), fat (2.34%), and ash (0.80%) contents (P < 0.05). Furthermore, proteins recovered from SPW (SPWP) and FSW (FSWP), CSW (CSWP), PSW (PSWP), and GSW (GSWP) presented yield, protein, fat, ash, and moisture content in the range of 55.54-76.81%, 65.86-78.22%, 7.26-11.45%, 4.58-11.75%, and 5.67-14.79%. All protein samples displayed higher essential amino acid (EAA) content with leucine (8.47-14.52 g/100 g) as a predominant amino acid. GSWP and SPWP scored the highest and lowest EAA contents, respectively. SPWP displayed myofibrillar proteins as dominant proteins, while slaughterhouses' wastewater proteins showed blood proteins as major proteins. ß-Sheet is the major secondary structure presented by all protein samples. SPWP showed the highest lightness value as compared to other protein counterparts (P < 0.05). All protein samples from slaughterhouse wastewaters had the lowest protein solubility at pH 4.5. However, SPWP presented minimum solubility at pH 5.5. Among all protein samples, SPWP presented slightly higher water holding capacity and foaming property (P < 0.05), whereas FSWP displayed slightly higher emulsion property (P < 0.05). Overall, all meat processing wastewater streams served as good sources of high-quality proteins, which could be used as protein ingredients in animal feed formulation.

Effects of ultrasound-assisted heating on aroma profile, peptide structure, peptide molecular weight, antioxidant activities and sensory characteristics of natural fish flavouring.

This study deals with the production of natural fish flavouring using ultrasound-assisted heating process. The effect of ultrasound pretreatment at different amplitudes (0, 15, 30, and 45%) on the Maillard reaction rate, antioxidant activities, flavour profile, and sensory characteristics of fish flavouring was investigated. Results showed that sonication markedly accelerated the Maillard reaction (MR) rate, as evidenced by the modification of peptide structure, a decrease in pH value, free amino acid content coupled with a rise in browning intensity. Also, ultrasound pretreatment significantly enhanced the antioxidant activities of fish flavouring (p ≤ 0.05). Moreover, sonication increased the type and content of aroma compounds significantly. Sensory analysis revealed that ultrasound pretreatment increased the fish-like and toasty aroma as well as umami and mouthfulness attributes coupled with the reduction of the bitter taste of the fish flavouring. This result was consistent with the GC-MS, electronic nose, cluster, and Partial Least Squares Regression (PLSR) analyses, which clearly showed that ultrasound pretreatment enhanced the fish-like aroma, which was associated with the increase in aldehydes, ketones, alcohols, thiophenes, pyrazine, and furans contents. Thus, it could be concluded that ultrasound pretreatment, coupled with the thermal process, could be a promising process for the production of natural fish flavouring with higher antioxidant activities.

Effects of different pretreatments and proteases on recovery, umami taste compound contents and antioxidant potentials of Labeo rohita head protein hydrolysates.

Effects of the pretreatments namely heating, microwave (MW), and ultrasound (US), followed by the enzymatic hydrolysis using different proteases (flavourzyme, neutrase, and protamex) on the protein recovery, umami taste compound content, and antioxidant activities of the Labeo rohita head (LRH) protein hydrolysate was investigated. US and MW pretreatments increased the protein recovery, MSG-like amino acid and flavour 5'-nucleotide contents, equivalent umami concentration (EUC) and antioxidant activities of LRH protein hydrolysates significantly (p < 0.05). The type of enzyme influenced the protein recovery and EUC significantly but did not influence the flavour 5'-nucleotide content of LRH protein hydrolysate (p > 0.05). The highest recovery yield of LRH protein hydrolysate (69.75%) was obtained with the MW pretreatment followed by the protamex hydrolysis, while the highest EUC (41.82 g monosodium glutamate (MSG)/kg) was yielded with the combination of the US pretreatment and the flavourzyme hydrolysis. These results indicate that US and MW pretreatments can help to enhance the recovery yield, umami taste compound content and antioxidant activities of the LRH protein hydrolysate.

Influence of spray-drying, freeze-drying and vacuum-drying on physicochemical and functional properties of gelatin from Labeo rohita swim bladder.

Influence of different drying method on yield, physicochemical and functional properties of gelatin from rohu (Labeo rohita) swim bladder were investigated. Freeze-drying presented the highest gelatin yield (54.51 g/100 g, dry weight basis), followed by vacuum-drying (48.95 g/100 g) and spray-drying (41.76 g/100 g), respectively (P < 0.05). All gelatin samples showed glycine as the major amino acid followed by proline, glutamic acid, alanine, arginine and hydroxyproline, respectively. Freeze-dried gelatin (FDG) and spray-dried gelatin (SDG) showed α (α1 and α2), ß-chains and γ-chain as the predominant components, whereas an absence of ß- and γ-chains found in vacuum-dried gelatin (VDG). FTIR spectra revealed that the loss of the triple-helix was found in all gelatins which indicated the conversion of collagen to soluble gelatin. FDG and SDG had the highest surface hydrophobicity, protein solubility, emulsifying, foaming and gelation property than VDG (P < 0.05). Moreover, SDG showed slightly higher surface hydrophobicity, protein solubility, emulsifying and foaming properties as compared to FDG (P < 0.05). However, no significant difference was found in gelation properties of FDG and SDG (P > 0.05). Therefore, freeze-drying or spray-drying could be an appropriate drying method for preparation of gelatin from rohu swim bladder with better functionalities.

Effect of various acids on physicochemical and functional characteristics of gelatin from swim bladder of rohu (Labeo rohita).

Influence of various acids (acetic acid, phosphoric acid, and propionic acid) at different concentrations (0.05, 0.1, and 0.2 M) on the extraction yield, physicochemical and functional properties of gelatin from Labeo rohita swim bladder were investigated. Highest gelatin yield (44.22%, dry weight basis) was obtained in a sample prepared by without acid pretreatment (GWA) of swim bladder as compared to acid pretreatment counterparts. Amongst the acid pretreatments, propionic acid (GPrA) showed the highest gelatin yield, followed by acetic acid (GAA) and phosphoric acid (GPA) at all concentrations used, respectively. Moreover, with increased concentrations of all acids, the decrease in gelatin yield was observed for all the acids. GWA showed higher protein and hydroxyproline content than that of acid counterparts (P < 0.05). Amino acid analysis of gelatins showed glycine as the major amino acid in all gelatins followed by proline, glutamic acid and alanine, respectively. GWA showed α (α1 and α2) and ß-chains as the predominant components with low molecular weight peptides. However, GPrA, GAA, and GPA had α1 and α2 dominant constituents. FTIR spectra of gelatins revealed that the loss of the triple-helix was found in GPA, GAA, and GPrA, compared to GWA. Among gelatin samples, GWA showed the highest solubility at all pH tested followed by GPrA, GPA, and GAA respectively. Furthermore, GWA exhibited higher emulsifying, foaming and gelling properties as compared to GPrA, GPA, and GAA, respectively. Therefore, the acid pretreatment of swim bladder had a negative impact on the extraction yield, physicochemical and functional properties of gelatin from rohu swim bladder.

Physicochemical and functional properties of beany flavour-free bambara groundnut protein isolate.

BACKGROUND: Off-odour/flavour (beany) associated with bambara groundnut protein isolate (BGPI), due to oxidative degradation of lipids during either storage or processing, is a major problem limiting its application in foods. In this study, effects of heat treatment (50-80 °C) in combination with ethylenediaminetetraacetic acid (EDTA) on functional and sensory properties of BGPI were investigated. RESULTS: BGPI prepared in the presence of EDTA had lower lipoxygenase and trypsin-inhibitory activities than BGPI prepared in the absence of EDTA, regardless of the heating temperature used (P < 0.05). Inactivation of lipoxygenase was associated with lowered peroxide value, thiobarbituric acid-reactive substances and beany odour/flavour intensity in BGPI stored at room temperature for 30 days. BGPI with heat treatment at temperatures lower than 70 °C had similar protein patterns to BGPI prepared by the typical process, except for the occurrence of proteins with molecular weight 70-82 kDa. BGPI with heat treatment showed decreased protein solubility but increased surface hydrophobicity and sulfhydryl group content. BGPI prepared in the presence of EDTA exhibited higher emulsion activity and stability indices as well as higher foam expansion and stability than BGPI prepared in the absence of EDTA, regardless of heating temperature (P < 0.05). CONCLUSION: Heat treatment at 70 °C in the presence of 100 mmol L(-1) EDTA effectively reduced beany flavour development and enhanced the functionality of BGPI.

Effects of binary organic solvents and heating on lipid removal and the reduction of beany odour in Bambara groundnut (Vigna subterranean) flour.

Effects of various binary organic solvents at different temperatures on the removal of lipids and beany or grassy odour of Bambara groundnut flour were studied. The highest lipid removal was achieved at 60°C (P<0.05), regardless of binary organic solvents used. Under the optimal temperature, chloroform/methanol showed the highest lipid removal (87%), followed by hexane/isopropanol (78%). All binary solvents containing methanol had higher efficiency in removal of phospholipids, and inactivation of lipoxygenase and trypsin inhibitors, as compared to isopropanol containing solvents (P<0.05). Based on FTIR spectra, lipids removed by methanol containing solvents had high content of phospholipids. The flours defatted by methanol containing solvents exhibited the lowest peroxide value, thiobarbituric acid-reactive substances and beany odour intensity than the non-defatted flour and those defatted by isopropanol containing solvents throughout the storage (P<0.05) of 30days at refrigerated and room temperatures. In general, chloroform/methanol was the most effective in inactivating lipoxygenase and trypsin inhibitors, retarding lipid oxidation as well as beany odour development in flour. Therefore, chloroform/methanol could be used to lower beany or grassy odour in Bambara groundnut flour.

Comparative study on chemical compositions and properties of protein isolates from mung bean, black bean and bambara groundnut.

BACKGROUND: Different legume seeds may have different protein compositions and properties, thereby affecting applications in food systems. This study aimed to extract and characterize protein isolates from legumes grown in Thailand, including mung bean (MBPI), black bean (BBPI) and bambara groundnut (BGPI). RESULTS: All protein isolates had a protein content in the range of 85.2-88.2%. The highest trypsin inhibitory activity was found in BGPI. All protein isolates exhibited satisfactory balanced amino acids with respect to the FAO/WHO pattern. MBPI and BBPI had three predominant proteins with a molecular weight (MW) range of 42-54 kDa, whereas BGPI had two dominant proteins with MW of 52 and 62 kDa. Based on differential scanning calorimetric analysis, MBPI and BGPI had two endothermic peaks, whereas three peaks were found for BBPI. All protein isolates exhibited similar FTIR spectra, indicating similarity in functional group and structure. All protein isolates showed a minimum protein solubility at around pH 4-5. CONCLUSION: All protein isolates were important sources of proteins with high lysine content. Isolates from different legumes showed slight differences in physiochemical and thermal properties. Those isolates can be used as proteinaceous ingredients in a variety of food products such as salad dressing, meat products and desserts.