Enzyme-assisted Aqueous Extraction Research Articles

Effects of sucrase enzymatic hydrolysis combined with Maillard reaction on soy protein hydrolysates: Bitterness and functional properties

In this study, sucrase was added to convert non-reducing sugars into reducing sugars in skim obtained by enzyme-assisted aqueous extraction processing (EAEP), then the variation of soy protein hydrolysates (SPH) from the skim under different Maillard reaction times were studied. We conducted one-factor experiment and selected 2 mg/mL sucrase for enzymatic hydrolysis for 2 h. The structure of SPH was investigated by Fourier transform infrared spectroscopy, intrinsic fluorescence spectroscopy, and amino acid composition. Results showed that the Maillard reaction loosened the SPH structure and produced new functional groups. Sensory evaluation, electronic tongue, electronic nose and GC–MS were used to study the sensory characteristics of SPH, we found that the bitterness value was significantly reduced to 1.71 from 4.63 after 2 h of the Maillard reaction. The change of bitterness was related to amino acid composition and the production of pyrazine. Additionally, the iron reduction ability, DPPH free radical scavenging ability, and emulsifying activity reached the highest at 2 h of reaction with 0.80, 73.94 %, and 56.09 %. The solubility, emulsifying stability, and foaming capacity increased and gradually stabilized with the increasing reaction time. Therefore, this paper presents an effective method for generating SPH with low bitterness and high functional properties.

Enzyme-assisted aqueous extraction of fish oil from Baltic herring (Clupea harengus membras) with special reference to emulsion-formation, extraction efficiency, and composition of crude oil.

Enzyme-assisted aqueous extraction (EAAE) is a green, and scalable method to produce oil and protein hydrolysates from fish. This study investigated the role of different parameters on emulsion formation, oil recovery, and the composition of crude oil during EAAE of Baltic herring (Clupea harengus membras). Fatty acid compositions, lipid classes, tocopherols, and oxidation status of the EAAE crude oils were studied. Compared to solvent-extracted oil, EAAE resulted in a lower content of phospholipids accompanied by a 57% decrease in docosahexaenoic acid. Changing fish to water ratio from 1:1 to 2:1 (w/w) with ethanol addition led to the greatest reduction (72%) of emulsion, which resulted in an increase in oil recovery by 11%. The addition of ethanol alone, or reduction of enzyme concentration from 0.4% to 0.1% also reduced emulsion-formation significantly. Overall, emulsion reduction resulted in higher content of triacylglycerols and n-3 polyunsaturated fatty acids in the crude oil extracted.

Pumpkin seed oil: A comprehensive review of extraction methods, nutritional constituents and health benefits.

Pumpkin seed oil (PSO), a rich source of nutrient contents, is extracted from the seeds of different pumpkin varieties for food and medicine industries. Accordingly, this article was designed to provide an evidence-based review of the literature, with the purpose of achieving practical conclusions involved the extraction technologies, nutritional properties, and validated biological activities of PSO. From the previous literatures, PSOs contain a large proportion of unsaturated fatty acids, with linoleic acid as the main component, and an amount of tocopherol, phytosterol, and phenolic acids. Some differences in the yield, composition and physicochemical properties of PSO can be associated with the pumpkin's cultivars and the extraction methods. Some novel technologies involved in supercritical fluid extraction, enzyme-assisted aqueous extraction, ultrasound-assisted extraction have been gradually replacing the conventional technologies as the most promising method which promote safe, non-polluting and effective recovery of PSO. This healthy vegetable oil was reported by several in vitro and in vivo studies to have potential protective roles in oxidative stress, inflammation, cancer, and cardiovascular diseases. This article is protected by copyright. All rights reserved.

Optimization of Enzyme-Assisted Aqueous Extraction of Polysaccharide from Acanthopanax senticosus and Comparison of Physicochemical Properties and Bioactivities of Polysaccharides with Different Molecular Weights.

To obtain the optimal process for the enzyme-assisted aqueous extraction of polysaccharides from Acanthopanax senticosus, and study the physicochemical properties of polysaccharides of different molecular weights, the extraction of Acanthopanax polysaccharides was optimized using the BBD response surface test. The polysaccharides with different molecular weights were obtained by ethanol-graded precipitation at 40%, 60%, and 80%, which were presented as ASPS40, ASPS60, and ASPS80. The polysaccharides were analyzed by HPGPC, ion chromatography, FT-IR, UV, SEM, TGA, XRD, Congo red, and I2-KI tests. The antioxidant assay was used to evaluate their antioxidant properties in vitro. The findings demonstrated that the recovery rate of Acanthopanax polysaccharide was 10.53 ± 0.682%, which is about 2.5 times greater compared to the conventional method of hot water extraction. Based on FT-IR, TGA, polysaccharides with different molecular weights did not differ in their structure or thermal stability. The XRD suggests that the internal structure of ASPSs is amorphous. Congo red and I2-KI showed that all three polysaccharides had triple helix structures with longer branched chains and more side chains. Furthermore, the antioxidant results showed the antioxidant activity of polysaccharides is not only related to the molecular weight size but also can be related to its composition and structure. These studies developed a green, and scalable method to produce polysaccharides from Acanthopanax senticosus and evaluated the properties of Acanthopanax polysaccharides of different molecular weights.

A sequential fractionation approach to understanding the physicochemical and functional properties of aqueous and enzyme-assisted aqueous extracted black bean proteins

Black bean proteins were sequentially extracted and characterized to determine the contribution of protein classes to the extractability, thermal behavior, and functionality of protein extracts produced by aqueous (AEP) and enzyme-assisted aqueous extraction processes (EAEP). Osborne fractionation showed that 56% of black bean proteins were water-soluble (albumin-rich), 22% salt-soluble (globulin-rich), 16% alkaline-soluble (glutelin-rich) and 0.65% alcohol-soluble (prolamin-rich). Protein extraction yields of 75 and 81% were achieved by AEP (pH 9.0, 50 °C, 1:10 solids-to-liquid ratio, 60 min) and EAEP (same conditions as AEP with 0.5% (w/w) alkaline protease), respectively. Gel electrophoresis demonstrated differences in the protein molecular weight profile in each fraction, as well as extensive proteolysis of major storage proteins in the EAEP. Proteomics revealed that similar proteins were present among the albumin-, globulin-, and glutelin-rich fractions, but in different proportions to yield distinct protein profiles. AEP and EAEP proteins had similar denaturation temperatures (Td = 92 °C) but were lower than the albumin- and globulin-rich fractions. There was not a clear association between solubility, emulsifying, and foaming properties for the protein classes, which highlighted the complex nature of the protein extracts, as well as potential impacts of the honogemization process on the surface properties of the proteins. Proteolysis significantly increased solubility at pH 4.5 (50 vs. 93%) and decreased foaming capacity at pH 4.5 and 7.0, while emulsifying capacity was not affected. Overall, the results demonstrate that enzyme-assisted extraction is a feasible method to increase black bean protein extractability while retaining thermal stability and modifying some functional properties.

Multi-dimensional analysis of heat-induced soybean protein hydrolysate gels subjected to ultrasound-assisted pH pretreatment

This study aimed to evaluate the gelation characteristics of soybean protein hydrolysate (SPH) extracted by enzyme-assisted aqueous extraction. Specifically, the changes in gelation behaviors for heat-induced (95 °C, 20 min) SPH dispersions treated with pH (pH 3, 5, 9; pH 7 as control) and ultrasound (U; 240 W, 30 min) were investigated. The results showed that typical gel behavior with high elastic nature in the viscoelasticity and network structures were observed during the heating process, where the disulfide bond played a dominant role in the gel network formation of all the samples. Notably, the heat-induced aggregation in the SPH gels was mainly formed by the association of the basic B polypeptide in 11S and β subunit in 7S. The most superior SPH gel was formed at pH 7 when assisted by ultrasonication during the heating process. This as-synthesized gel showed a uniform filamentous structure and exhibited the more excellent textural, rheological and thermal properties than those of the samples formed under acidic and alkaline conditions. These results are of great value in revealing the gelation mechanism of SPH.

One positive part of copper ion on biocatalysts: CNPs@Cu-Trypsin-assisted aqueous extraction technique for simultaneous exploration of edible insect oil and protein

Edible insects are rich in oil and protein resources, and has it become increasingly important to develop them reasonably when resources are increasingly scarce. However, due to the challenges in recovering enzymes in the enzyme-assisted aqueous extraction technique and the remaining organic solvents in the extraction process based on organic solvent, it is difficult to achieve simultaneous utilization of oil and protein from edible insects. Hence, an improved enzyme-assisted aqueous extraction process based on the assistance of chitosan cross-linked Fe3O4 nanoparticles (CNPs) immobilized enzymes and divalent copper ions chelation, CNPs@Cu-Trypsin-assisted aqueous extraction technique, was first proposed. The hydrolysis activity was significantly increased by 6.16 times, and the value of Kcat/Km was increased by 1.7 times for the results of the formation of the hydrophilic microenvironment. Furthermore, the extraction ratio of silkworm pupae oil extracted via CNPs@Cu-Trypsin-assisted aqueous extraction technique could be increased to 93%, and the oil extraction rate could be maintained above 65% after 10 times reused. Improvement of enzyme-assisted aqueous extraction under the addition of divalent copper ions could achieve an ideal effect of oil extracted from silkworm pupae with less time. Additionally, the quality of silkworm pupae oil was significantly improved and the silkworm pupae protein hydrolysate also showed improved biological activity. Therefore, the enzyme-assisted aqueous extraction enhancement by trypsin immobilization and divalent copper ion chelation is a promising strategy for the green and sustainable exploration of edible insect oil and protein without the use of organic solvents.

Effects of different aqueous extraction techniques on physicochemical quality and oil recovery of sesame oil

Sesame is the oldest oilseed crop in agriculture, and it produces more oil than any other crop on the planet. This research aimed to investigate the impact of different oil extraction procedures on sesame seed oil physicochemical quality and oil recovery. The oil was extracted from the clean and healthy seeds using four extraction methods: aqueous, enzyme-assisted aqueous, ultrasound-assisted aqueous and solvent extraction using the Soxhlet apparatus. It was observed that ultrasound-assisted aqueous extracted oil had maximum saponification value and minimum acid value, refractive index, and lower free fatty acid value, compared with aqueous extracted oil and enzyme-assisted aqueous extracted oil. Ultrasound-assisted aqueous extraction method also yielded maximum oil, retrieval followed by enzyme-assisted aqueous extraction and aqueous extraction.

Effect of enzyme types on emulsifying properties of walnut emulsion

In order to explore the efficient investigate and utilization of emulsion produced by enzyme-assisted aqueous extraction of walnut oil, the effects of different enzyme treatment (including Alcalase 2.4L, Ban 480L α-amylase, Neutrase 0.8L, Pectinex SP-L, Celluclast 1.5L) on the characteristics of emulsion were studied to characterize its emulsifying characteristics The emulsion composition, particle size distribution, Zeta potential, rheological properties and protein surface hydrophobicity of emulsion were determined to characterize its emulsifying properties. The results showed that the particle size of the emulsion obtained from enzymatic hydrolysis showed a smaller trend and the absolute value of Zeta potential showed a larger trend in the presence of enzymes. On emulsion protein, hydrophobicity of emulsion protein was obtained by hydrolysis with different enzymes showed that the trend followed the order: Celluclast 1.5L> Ban 480L >Neutrase 0.8L >Pectinex SP-L >control> Alcalase 2.4L. The particle size, zeta potential, ability to increase emulsion viscosity and interfacial hydrophobicity of emulsion proteins affected the emulsion physical stability and the effect of demulsification. The results of rheological analysis show that emulsions from Ban 480L α-amylase, Neutrase 0.8L and Celluclast 1.5L hydrolysate still maintained their elastic structure damaged by shear rate and were more stable, and the emulsions obtained by Alcalase 2.4L and Pectinex SP-L were unstable which was easy to be broken.

Quality characteristics and volatile compounds of oil extracted from njangsa seed

AbstractUnconventional and underutilized plant oils are increasing popular and helping to meet demand for food, health and other industrial application. In recent years, the search for alternative sources that deliver healthful benefits, low‐environmental impact and ethical responsibility have become a priority to both scientists and industry. Oil from njangsa seed (Ricinodendron heudelotti) was recovered using four selected enzymes—hemicellulase, protease, pectinase, and amylase in an enzyme‐assisted aqueous extraction (EAE) and the recovery, quality indices and fatty acid composition was compared to solvent extraction using hexane (HE). Njangsa seed oil (NSO) recovered from the EAE ranged between 29 and 36% and were significantly (p < 0.05) lower than HE (46%), and the quality indices (free fatty acid, peroxide, para‐anisidine, and thiobarbituric acid values) were consistently lower and better than HE‐NSO. The fatty acid profile of EAE‐NSO was qualitatively and quantitatively comparable to HE‐NSO, with differences among the enzymes used. Alpha‐eleostearic acid was the most abundant fatty acid and was consistently ca 41% among the samples. Among the volatile compounds analyzed on the polar and nonpolar columns, 13 (2 alcohols, 9 aldehydes, and 2 esters) were detected in EAE‐NSO using hemicellulase, and 35 (4 aldehydes, 1 ester, and 30 hydrocarbons) in HE‐NSO. The most abundant flavor compounds identified were pentanal, methylcyclopentane, cyclohexane, 3‐methylpentane, (E,E)‐2,4‐nonadienal, (E)‐2‐heptenal, hexanal, 1‐butanol, and butanal. This study suggests that the amount, quality, and content of oil and volatile compounds in NSO can be influenced by the choice of extractant.

A STUDY ON CHARACTERIZATION OF PECTINASE ASSISTED AQUEOUS EXTRACTION OF RICE BRAN OIL

The Rice bran oil is known as wonder oil because of its numerous health benefits. It has a number of advantages over other edible oils because of the presence of antioxidant known as oryzanol. The rice bran contains 10-26% oil depending on the factors like variety, milling process, and other conditions. Various solvents are currently used for rice bran oil extraction process at industrial sectors. These solvents are carcinogenic and also cause adverse effects to the environment. The enzyme-assisted aqueous extraction process has been regarded as an eco-friendly process. Pectinase enzyme is used to break down complex carbohydrates like pectin present in rice bran and allows easy oil extraction in aqueous solution. The present study aims to perform the aqueous extraction of rice bran oil using crude pectinase enzyme extracted from the pectinase producing bacteria Bacillus paramycoides and to study the oil characteristics. Out of the various solvents used in the study, hexane yielded highest percentage of oil. The oil yield was found to be 49.8% in 6 h. The total activity of enzyme was found to be 11 U/mL/min. 500 Units of enzyme was taken for rice bran oil extraction. The Average yield of oil was found to be 80.5% in 3 h and 76.9% in 6 h. The acid value, saponification value, iodine value and oryzanol content of the oil was found to be11.22, 84.15, 5.0 and 0.05 percentage respectively. The percentage of radical scavenging activity of the extracted rice bran oil was found to be 49.51%. The fatty acids present in the oil sample were analyzed by GC MS analysis.

Understanding the impact of enzyme-assisted aqueous extraction on the structural, physicochemical, and functional properties of protein extracts from full-fat almond flour

The need for sustainable protein sources has prompted research on several plant-based protein matrices. The effects of enzymatic extraction on the composition, physicochemical, structural, and functional properties of protein-extracts (skim) from full-fat almond flour were elucidated. Protein-extracts were produced by aqueous (AEP), and enzyme-assisted extraction processes (EAEP), which enable concurrent extraction and fractionation of lipids and proteins without the use of flammable solvents. Except for the use of 0.5% of protease in the EAEP, extraction parameters were similar for both processes (pH 9.0, 50 °C, 1:10 solids-to-liquid ratio, and 60 min). The use of enzyme to assist the extraction resulted in the production of protein extracts with higher protein content and promoted the formation of smaller peptides and a more unordered protein secondary structure with reduced surface hydrophobicity. These structural modifications reduced the EAEP skim protein thermostability and improved its water absorption capacity (2.4 vs. 2.7 g water/g protein) compared with the AEP proteins. Importantly, proteolysis significantly enhanced the functionality of the hydrolysates at pH values close to the almond protein isoelectric point. At pH 5.0, EAEP skim proteins had higher solubility (47 vs 23%), emulsification capacity (492 vs 402 g oil/g protein), emulsification activity index (35 vs 17 m2/g) and foaming capacity (23 vs 11%) compared with AEP proteins. These results indicate that moderate hydrolysis can be used to improve extractability and the functionality of almond proteins, creating new opportunities for its application as food ingredients.

Optimization and Evaluation of Hydration Method for Cold Recovery of Oils and Defatted Meal from Pinus armandi Seed Kernels.

Large quantities of oils and proteins are demanded per year while their production needs environmentally friendly (green), safe, low cost, efficient and sustainable methods. Hydration method for producing Pinus armandi seed kernel oil and defatted meal rich in proteins was therefore developed, which had the following optimal conditions: baking kernels at 130 °C for 10 min, grinding them to pass through a 80-mesh sieve, mixing the ground kernel (10.00 g) with 1.00 mL of 8% brine or water and agitating at room temperature for 30 min. This method recovered 96.71% edible oil with vitamin E and K, phytosterols, carotenoids and squalene concentrated and de-oiled meal containing 57.98% proteins and 4.17% oils with ascorbic acid, thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, folate, total phenolic and flavonoids concentrated. It had higher recovery rate and other physicochemical indices of edible oil and was found to be more sustainable as compared with cold pressing, enzyme-assisted aqueous extraction and solvent extraction.

Flavonoids from Fig (Ficus carica Linn.) Leaves: The Development of a New Extraction Method and Identification by UPLC-QTOF-MS/MS

Flavonoid-rich leaves of the Ficus carica L. plant are usually discarded as waste. In this work, ultrasonic enzyme-assisted aqueous two-phase extraction (UEAATPE) was proposed as an innovative method to estimate the total flavonoids present in F. carica L. leaves. Total flavonoids were analyzed qualitatively and quantitatively by UPLC-QTOF-MS. At 38% (w/w) ethanol/18% (w/w) ammonium sulfate, we achieved the optimum conditions in which to establish an easy-to-form aqueous two-phase extraction (ATPE) as the final system. The optimal UEAATPE conditions were set at an enzymatic concentration of 0.4 U/g, 150 min enzymolysis time, an enzymolysis temperature of 50 °C, a liquid–solid ratio of 20:1 (mL/g), and 30 min ultrasonic time. The yields of the total flavonoids, i.e., 60.22 mg/g, obtained by UEAATPE were found to be 1.13-fold, 1.21-fold, 1.27-fold, and 2.43-fold higher than those obtained by enzyme-assisted ATPE (EAATPE), ultrasonic-assisted ATPE (UAATPE), ATPE, and soxhlet extraction (SE) methods, respectively. Furthermore, eleven flavonoids from the leaves of the F. carica L. plant were completely identified and fully characterized. Among them, ten flavonoids have been identified for the first time from the leaves of the F. carica L. plant. These flavonoids are quercetin 3-O-hexobioside-7-O-hexoside, 2-carboxyl-1,4-naphthohydroquinone-4-O-hexoside, luteolin 6-C-hexoside, 8-C-pentoside, kaempferol 6-C-hexoside-8-C-hexoside, quercetin 6-C-hexobioside, kaempferol 6-C-hexoside-8-C-hexoside, apigenin 2″-O-pentoside, apigenin 6-C-hexoside, quercetin 3-O-hexoside, and kaempferol 3-O-hexobioside. Therefore, F. carica L. leaves contain new kinds of unidentified natural flavonoids and are a rich source of biological activity. Therefore, this research has potential applications and great value in waste handling and utilization.

Techno-Economic Analysis of Integrating Soybean Biorefinery Products into Corn-Based Ethanol Fermentation Operations

With the development of agricultural biorefineries and bioprocessing operations, understanding the economic efficiencies and environmental impacts for these have gradually become popular for the deployment of these industrial processes. The corn-based ethanol and soybean oil refining industries have been examined extensively over the years, especially details of processing technologies, including materials, reaction controls, equipment, and industrial applications. The study focused on examining the production efficiency changes and economic impacts of integrating products from the enzyme-assisted aqueous extraction processing (EAEP) of soybeans into corn-based ethanol fermentation processing. Using SuperPro Designer to simulate production of corn-based ethanol at either 40 million gallons per year (MGY) or 120 MGY, with either oil separation or no oil removal, we found that indeed integrating soy products into corn ethanol fermentation may be slightly more expensive in terms of production costs, but economic returns justify this integration due to substantially greater quantities of ethanol, distillers corn oil, and distillers dried grains with solubles being produced.

Optimization of cold press and enzymatic‐assisted aqueous oil extraction from tomato seed by response surface methodology: Effect on quality characteristics

Tomato seeds, which are the byproducts of tomato paste processing, were used to obtain tomato seed oil using two different extraction methods: cold press extraction (CPE) and enzyme-assisted aqueous extraction (EAAE). To maximize oil amount, the experimental parameters of those two methods were optimized separately by response surface methodology. The optimized methods were used to evaluate their quality characteristics. The maximum oil amounts for tomato seed oil using CPE and EAAE were found as 12.80% and 9.66%, respectively. These obtained results present important information for the determination quality characteristics including the physical, chemical, microbiological, and bioactivity properties of tomato seed oil in both extraction methods used. The comparison of two methods shows that they are both ecology friendly extraction methods. It also helps to a great extend to evaluate quality characteristics and bioactivity properties of tomato seed oil. Therefore, tomato seed oils extracted by two methods are promising for future usage as functional food. This manuscript will comprise the basis of our future studies analyzing the new compounds obtained from agro-food waste. Practical applications Recently, world agricultural and food sector has faced an important problem, which is food waste. Food wastes have the high-value compounds such as carbohydrates, protein, lipids, nutraceuticals, etc. The wastage of these high-value compounds causes both an environmental and economical problems. To come up with this problem, there is a need for green and sustainable approaches leading to extract of these compounds with low environmental impact. We extracted tomato seed oil using two different green technologies and also evaluated their quality and functional properties, whether they use as food additives, preservatives, texturizing agent, coloring agents, etc. Two different extraction methods were optimized separately by response surface methodology to maximize oil amounts. Both tomato seed oils might be used as a good alternative in future in the preventing and therapeutic strategies.

Effect of different extraction methods on trace metal elements content of Persian lime (Citrus latifolia) seed oil

The oil of Persian lime (Citrus latifolia) seed was extracted using three methods (cold-pressing, solvent extraction and enzyme-assisted aqueous extraction using Protamex and Celluclast) to compare the effect of extraction method on oil quality through trace metal elements (Fe, Cu, Ni, Co, Pb and As) content. The results demonstrated that extraction method significantly (P < 0.05) influences the trace metal elements content of oil. The reduction pattern of Fe > Cu > Ni > Co > Pb > As was observed in Persian lime seed and extracted oil samples. The highest concentration (mg/kg) of iron (7.3272 ± 0.0263), copper (0.350033 ± 0.00153) and lead (0.00891 ± 0.00003) were observed in cold pressed oils. The oils extracted using enzyme-assisted aqueous extraction method showed the highest concentration (mg/kg) of nickel (0.069855 ± 0.000167) and cobalt (0.054555 ± 0.000163). Arsenic was not detected in seeds and any of the extracted oil samples. The concentration of Fe (3.0363 ± 0.0423 mg/kg) and Cu (0.280167 ± 0.00151 mg/kg) as a pro-oxidant was lower in the Persian lime seed oil obtained by enzyme-assisted aqueous extraction method.

Carotenoids and antioxidant activity in virgin palm oil (VPO) produced from palm mesocarp with low heat aqueous-enzyme extraction techniques

Abstract Palm oil is known for its vitamin E as well as other phytonutrients including carotenoids, phytosterols, and phenolic compounds. Red palm oil also known as the virgin palm oil (VPO) has the potential for nutraceutical application as well as for household use as it contains an abundance amount of phytonutrients with many functional properties. The objective of the study was to measure the oil recovery and phytonutrients content of VPO produced by the low-heat enzyme-assisted aqueous extraction (EAAE) method and to compare with the non-enzyme treated mesocarp. Pectinase from Aspergillus niger was used as the enzyme treatment in the EAAE method. The percentage of oil yield, total phenolic content, antioxidant activity and total carotenoids were evaluated. The effects of different enzyme concentration on the phytonutrients were also determined. The percentage of oil yield from the enzyme-treated mesocarp is significantly higher (52.7% v/w) than the non-enzyme treated oil (26.11% v/w). The carotenoid content in the EAAE extracted VPO obtained is between 35 and 40 mg/100 g sample. The carotenoids and the total phenolic content between the EAAE and non EAAE extracted oil are not significantly different, however, the antioxidant activity of EAAE extracted oil is significantly higher at 21% than the non-enzyme treated oil. The enzyme concentration at 4.5% was found to increase the oil yield by 200%. The study showed that the EAAE method can increase the oil yield as well as the antioxidant activity of VPO. Thus, the enzyme assisted-aqueous extraction method can be used to produce a high-quality VPO with high oil recovery and high antioxidant activity.

Enzyme-Assisted Aqueous Extraction of Cobia Liver Oil and Protein Hydrolysates with Antioxidant Activity

Cobia, Rachycentron canadum, is a medium-size marine fish with emerging global potential for offshore aquaculture. The processing waste, cobia liver, is a raw material rich in polyunsaturated fatty acid oils. In this study, an environmentally friendly green process, aqueous extraction (AE), was used to extract the cobia liver oil. The effect of cooking time and substrate water ratio on the oil extractability was investigated herein. The cooking time of 15 min, and substrate water ratio of 1:2 obtained the highest extraction efficiency. However, the oil extractability was only 18.8%. Thus, enzyme-assisted aqueous extraction (EAAE) was used to increase oil extractability and recovery of protein hydrolysates. The commercial proteases—including alcalase, papain, trypsin, and pepsin—were employed in pretreated cobia liver in order to increase oil release during AE. The EAAE results showed that maximum oil extractability was 38% by papain pretreatment. EAAE greatly improved the extraction efficiency; the oil extractability was double than that of AE (18.8%). The fatty acid profiles revealed that ω-3 polyunsaturated fatty acid contents of extracted oil obtained from AE and EAAE were 21.3% and 19.5%, respectively. Besides, the cobia liver hydrolysates obtained from EAAE by alcalase, papain, pepsin, and trypsin pretreatment showed scavenge DPPH radical activity with EC50 values of 0.92, 1.03, 0.83, and 0.53 mg, respectively. After in vitro simulated gastrointestinal digestion, the protein hydrolysates exhibited scavenge DPPH radical activity with EC50 values of 1.15, 1.55, 0.98, and 0.76 mg for alcalase, papain, pepsin, and trypsin, respectively. The study showed that the EAAE process can be used for extracting fish oil from fish waste while simultaneously obtaining the protein hydrolysates with antioxidant activity.

An innovative two-step enzyme-assisted aqueous extraction for the production of reduced bitterness soybean protein hydrolysates with high nutritional value

Soybean protein hydrolysates (SPH), by-product of enzyme-assisted aqueous extraction (EAEP), were a promising source of natural nutraceutical. Nevertheless, the bitterness of SPH has limited their use as food ingredients or additives. The objectives of the present study were to use two-step enzyme-assisted aqueous extraction to produce SPH with reduced bitterness and high nutritional value (antioxidant activity and peptide nitrogen levels). In this study, the optimum conditions for SPH production were obtained using Protex 6L (2 h) followed by Protease A 2SD (3 h) in two-step hydrolysis. The bitterness of SPH was positively correlated with the hydrophobic amino acids (Ala, Leu, Ile, Trp, Phe, Tyr) and hydrophobic peptide fractions. Additionally, the produced potential bitter peptides of SPH-6L were identified and predicted by LC-MS/MS and bioinformatics. IceLogo plot and heat map revealed that Protease A 2SD tends to cleave Leu and Arg residues from the N-terminal in bitter peptide to degrade bitter peptide. Thus, it could be concluded that the utilization of multi-enzyme hydrolysis, could be a promising process for the production of SPH with low bitter and potential antioxidant activity, which offers a promising approach for enhancing the usability and high-valued utilization of EAEP.