Optimization of enzymatic hydrolysis by alcalase and flavourzyme to enhance the antioxidant properties of jasmine rice bran protein hydrolysate

Optimizing the Conditions of Pretreatment and Enzymatic Hydrolysis of Sugarcane Bagasse for Bioethanol Production

The agricultural waste sugarcane bagasse (SCB) is a kind of plentiful biomass resource. In this study, different pretreatment methods (NaOH, H2SO4, and sodium percarbonate/glycerol) were utilized and compared. Among the three pretreatment methods, NaOH pretreatment was the most optimal method. Response surface methodology (RSM) was utilized to optimize NaOH pretreatment conditions. After optimization by RSM, the solid yield and lignin removal were 54.60 and 82.30% under the treatment of 1% NaOH, a time of 60 min, and a solid-to-liquid ratio of 1:15, respectively. Then, the enzymolysis conditions of cellulase for NaOH-treated SCB were optimized by RSM. Under the optimal enzymatic hydrolysis conditions (an enzyme dose of 18 FPU/g, a time of 64 h, and a solid-to-liquid ratio of 1:30), the actual yield of reducing sugar in the enzyme-treated hydrolysate was 443.52 mg/g SCB with a cellulose conversion rate of 85.33%. A bacterium, namely, Bacillus sp. EtOH, which produced ethanol and Baijiu aroma substances, was isolated from the high-temperature Daqu of Danquan Baijiu in our previous study. At last, when the strain EtOH was cultured for 36 h in a fermentation medium (reducing sugar from cellulase-treated SCB hydrolysate, yeast extract, and peptone), ethanol concentration reached 2.769 g/L (0.353%, v/v). The sugar-to-ethanol and SCB-to-ethanol yields were 13.85 and 11.81% in this study, respectively. In brief, after NaOH pretreatment, 1 g of original SCB produced 0.5460 g of NaOH-treated SCB. Then, after the enzymatic hydrolysis, reducing sugar yield (443.52 mg/g SCB) was obtained. Our study provided a suitable method for bioethanol production from SCB, which achieved efficient resource utilization of agricultural waste SCB.

Unraveling the biological potential of chicken viscera proteins: a study based on their enzymatic hydrolysis to obtain hydrolysates with antioxidant properties

Chicken meat production has increased over the years, leading to a proportional increase in waste generation, which often contains high levels of proteins, such as viscera. Therefore, this study aimed to investigate the enzymatic hydrolysis of chicken viscera proteins as a strategy to value solid waste from the poultry industry. The hydrolysates were characterized for their antioxidant properties and molecular weight distribution. Additionally, the enzymatic hydrolysis process was scaled up from 125 mL flasks with 50 mL of protein solution to 3 L using a 6 L bioreactor. The enzymatic hydrolysis of chicken viscera proteins using a binary mixture of proteases (85.25 U/mL of each enzyme, Alcalase and Flavourzyme, totaling 170.5 U/mL) resulted in an increase of up to 245% in 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, 353% 2,2-diphenyl-1-picryl-hydrazyl (DPPH) in radical scavenging, 69% in Ferric Reducing Antioxidant Power Assay (FRAP) and 146% in total reducing capacity (TRC). The antioxidant properties of the protein hydrolysates are preserved during the scale-up of enzymatic hydrolysis. Protein fractions smaller than 5 kDa showed the highest ABTS and DPPH radical scavenging activities, while fractions greater than 30 kDa showed the best results for the FRAP method.

Sustainable extraction of proteins from lime peels using ultrasound, deep eutectic solvents, and pressurized liquids, as a source of bioactive peptides

The aim of this work was to develop, for the first time, sustainable strategies, based on the use of Ultrasound-Assisted Extraction, Natural Deep Eutectic Solvents, and Pressurized Liquid Extraction, to extract proteins from lime (Citrus x latifolia) peels and to evaluate their potential to release bioactive peptides. PLE showed the largest extraction of proteins (66-69%), which were hydrolysed using three different enzymes (Alcalase 2.4 L FG, Alcalase®PURE 2.4 L, and Thermolysin). The in vitro antioxidant and antihypertensive activities of released peptides were evaluated. Although all hydrolysates showed antioxidant and antihypertensive activity, the hydrolysate obtained with Thermolysin showed the most significant values. Since the Total Phenolic Content in all hydrolysates was low, peptides were likely the main contributors to these bioactivities. Hydrolysates were analyzed by UHPLC-QTOF-MS and a total of 98 different peptides were identified. Most of these peptides were rich in amino acids associated with antioxidant activity.

Potential inhibitory effect of highland barley protein hydrolysates on the formation of advanced glycation end-products (AGEs): A mechanism study

Advanced glycation end products (AGEs) can be caused during a glycoxidation reaction. This reaction is associated with complications of diabetes and the consequences of health problems. Therefore, we are exploring the prohibitory effect of highland barley protein hydrolysates (HBPHs) on AGE formation. Herein, first extracted the protein from highland barley with various pH conditions and then hydrolyzed using four different proteolytic enzymes (flavourzyme, trypsin, papain, pepsin) under different degrees of hydrolysis. We assessed three degrees of hydrolysates (lowest, middle, highest) of enzymes used to characterize the antioxidant activity and physicochemical properties. Among all the hydrolysates, flavourzyme-treated hydrolysates F-1, F-2, and F-3 indicated the high ability to scavenge DPPH (IC50 values of 0.97 %, 0.63 %, and 0.90 %), structural and functional properties. Finally, the inhibitory effect of the most active hydrolysates F-1, F-2, and F-3 against the AGEs formation was evaluated in multiple glucose-glycated bovine serum albumin (BSA) systems. Additionally, in a BSA system, F-3 exhibited the strong antiglycation activity, effectively suppressed the non-fluorescent AGE (CML), and the fructosamine level. Moreover, it decreased carbonyl compounds while also preventing the loss of thiol groups. Our results would be beneficial in the application of the food industry as a potential antiglycation agent for several chronic diseases.

Impact of Time and Enzyme Concentration on Sangyod Rice Bran Hydrolysate: Phytochemicals, Antioxidants, Amino Acids, and Cytotoxicity

This study investigated the production of Sangyod rice bran hydrolysate (SYRB) from Sangyod rice, focusing on incubation times (1, 3, and 5 h) and alcalase enzyme concentrations (0, 0.7, and 1% v/v). The results demonstrated a concentration-dependent relationship: higher alcalase concentrations increased hydrolysate yield. Prolonged incubation, especially with alcalase, enhanced substrate breakdown, further increasing hydrolysate production. The degree of hydrolysis, reflecting peptide bond cleavage, depended on both incubation time and enzyme concentration, emphasizing the role of enzyme activity in efficiency. Moreover, color analysis (L*, a*, b*) and color difference (∆E) revealed intricate changes from enzymatic hydrolysis. Proximate composition analysis showed higher protein and lipid content with increased enzyme concentration and longer incubation times, whereas ash content varied with both factors. Hydrolysate powders exhibited higher moisture content than raw rice bran, indicating the impact of the hydrolysis process. The study also explored SYRB's antioxidant properties and cytotoxicity, which were sensitive to incubation time and alcalase concentration. Longer incubation increased DPPH scavenging activity, with the highest efficacy at 3 h. Meanwhile, ABTS scavenging displayed a delicate balance with alcalase concentration. The cytotoxicity study of SYRB revealed that all concentrations of SYRB were non-toxic to C2C12 cells, with cell viability values exceeding 70%.

Production and identification of immunomodulatory peptides in intestine cells obtained from hemp industrial by-products

Hemp seeds have attracted the interest of the food industry recently, to be employed as functional food, considering their nutritional composition, highlighting the high content and quality of the proteins. In this study, ten hemp protein hydrolysates (HPHs) were obtained by enzymatic hydrolysis with two food-grade proteases from a hemp protein isolate and the inflammatory properties were evaluated in Caco-2 cell line. To this end, the gene expression and the release of proinflammatory and anti-inflammatory cytokines by Caco-2 cells stimulated with bacterial lipopolysaccharide and treated with HPHs at concentrations of 50 and 100 μg/mL were analyzed. The peptides contained in each HPH were identified and those with higher quality of the match in the spectrum were subjected to in silico analyses to determine which peptides were bioactive and contributing to the immunomodulatory activity of the hydrolysates. The results suggest that the immunomodulatory properties of these HPHs could have a beneficial effect at the level of the intestinal epithelium. The HPH20A and HPH60A + 15F exerted high immunomodulatory properties based on the cytokine levels release. The oligopeptides MAEKEGFEWVSF and GLHLPSYTNTPQLVYIVK were proposed as the most active ones. The potential of these peptides as nutraceuticals to prevent or pretreat intestinal inflammation is promising, though requires validation by in vivo assays.

Antioxidant characteristics of hydrolysate from low-value sea cucumber: In vitro and in vivo activities of Caenorhabditis elegans

The antioxidant activity in vitro and in vivo of Actinopyga miliaris hydrolysate (AMH) was investigated. The proportion of oligopeptides with 150-1000 Da in AMH was 65.48%. The IC50 values of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), hydroxyl radical scavenging ability, and ferric ion reducing power of AMH were 0.37, 3.43, and 24.15 mg/mL, respectively. Compared with the control group, the body length of Caenorhabditis elegans fed with 8 mg/mL AMH extended from 632.08 μm to 1009.57 μm, and the swallowing frequency and head-swing frequency increased significantly. After being fed with AMH, the lifespan of C. elegans can be prolonged even under stress conditions, primarily due to superoxide dismutase activity, catalase activity, reduced glutathione content, and total antioxidant capacity in C. elegans increased, whereas reactive oxygen species level was reduced. The results showed that AMH had in vitro and in vivo antioxidant activity, which can alleviate oxidative damage and prolong life of C. elegans.

Development of Fortified Breads Enriched with Plant-Based Bioactive Peptides Derived from the Chia (Salvia hispanica L.) Expeller

By-products from the industrialization of oilseeds, particularly chia, can be sustainably used for the development of new functional products. In this work, wheat breads supplemented with up to 10 mg of chia expeller hydrolysate/g of flour were prepared, obtaining fortified breads with acceptability for consumption, according to a preliminary consumer research study based on an affective test employing a five-point hedonic scale of global acceptance. In this context, protein hydrolysates of the chia expeller were produced using Alcalase, reaching a degree of hydrolysis of 54.3 ± 1.6% with an antioxidant activity of 55.8 ± 0.4% after 6 h incubation at 25 °C in the presence of the enzyme. These peptides showed appropriate techno-functional properties and chemical compositions suitable for the further development of bakery products. Taken together, our approach and the development of a fortified bread with plant-based bioactive peptides provide a novel and eco-friendly alternative for the recovery of nutrients from agro-industrial waste. More importantly, these enriched breads could exert beneficial effects on human health by exploiting the antioxidant properties of functional peptides derived from the chia expeller.

Enzymatic Hydrolysis of Tenebrio molitor (Mealworm) Using Nuruk Extract Concentrate and an Evaluation of Its Nutritional, Functional, and Sensory Properties

Enzymatic protein hydrolysis is a well-established method for improving the quality of dietary proteins, including edible insects. Finding effective enzymes from natural sources is becoming increasingly important. This study used nuruk extract concentrate (NEC), an enzyme-rich fermentation starter, to produce protein hydrolysate from defatted Tenebrio molitor (also called mealworm, MW). The nutritional, functional, and sensorial properties of the hydrolysate were then compared to those obtained using commercial proteases (alcalase and flavourzyme). The protease activities of the crude nuruk extract (CNE), NEC, alcalase, and flavourzyme were 6.78, 12.71, 11.07, and 12.45 units/mL, respectively. The degree of hydrolysis and yield of MW hydrolysis by NEC were 15.10 and 35.92% (w/w), respectively. MW hydrolysate was obtained using NEC and had a significantly higher free amino acid content (90.37 mg/g) than alcalase (53.01 mg/g) and flavourzyme (79.64 mg/g) hydrolysates. Furthermore, the NEC hydrolysis of MW increased the antioxidant and angiotensin-converting enzyme inhibitory activity, with IC₅₀ values of 3.07 and 0.15 mg/mL, respectively. The enzymatic hydrolysis also improved sensory properties, including umaminess, sweetness, and saltiness. Overall, this study found that the NEC hydrolysis of MW outperformed commercial proteases regarding nutritional quality, sensory attributes, and biological activity. Therefore, nuruk could potentially replace commercial proteases, lowering the cost of enzymatic protein hydrolysis.

Trends in Biological Ammonia Production

Food production heavily depends on ammonia-containing fertilizers to improve crop yield and profitability. However, ammonia production is challenged by huge energy demands and the release of ~2% of global CO₂. To mitigate this challenge, many research efforts have been made to develop bioprocessing technologies to make biological ammonia. This review presents three different biological approaches that drive the biochemical mechanisms to convert nitrogen gas, bioresources, or waste to bio-ammonia. The use of advanced technologies-enzyme immobilization and microbial bioengineering-enhanced bio-ammonia production. This review also highlighted some challenges and research gaps that require researchers' attention for bio-ammonia to be industrially pragmatic.

Combined Neutrase-Alcalase Protein Hydrolysates from Hazelnut Meal, a Potential Functional Food Ingredient

Consumers' interest in functional foods has significantly increased in the past few years. Hazelnut meal, the main valuable byproduct of the hazelnut oil industry, is a rich source of proteins and bioactive peptides and thus has great potential to become a valuable functional ingredient. In this study, hazelnut protein hydrolysates obtained by a single or combined hydrolysis by Alcalase and Neutrase were mainly characterized for their physicochemical properties (SDS-PAGE, particle size distribution, Fourier-transform infrared (FTIR) spectroscopy, molecular weight distribution, etc.) and potential antiobesity effect (Free fatty acid (FFA) release inhibition), antioxidant activity (DPPH and ABTS methods), and emulsifying properties. The impact of a microfluidization pretreatment was also investigated. The combination of Alcalase with Neutrase permitted the highest degree of hydrolysis (DH; 15.57 ± 0.0%) of hazelnut protein isolate, which resulted in hydrolysates with the highest amount of low-molecular-weight peptides, as indicated by size exclusion chromatography (SEC) and SDS-PAGE. There was a positive correlation between the DH and the inhibition of FFA release by pancreatic lipase (PL), with a significant positive effect of microfluidization when followed by Alcalase hydrolysis. Microfluidization enhanced the emulsifying activity index (EAI) of protein isolates and hydrolysates. Low hydrolysis by Neutrase had the best effect on the EAI (84.32 ± 1.43 (NH) and 88.04 ± 2.22 m²/g (MFNH)), while a negative correlation between the emulsifying stability index (ESI) and the DH was observed. Again, the combined Alcalase-Neutrase hydrolysates displayed the highest radical scavenging activities (96.63 ± 1.06% DPPH and 98.31 ± 0.46% ABTS). FTIR results showed that the application of microfluidization caused the unfolding of the protein structure. The individual or combined application of the Alcalase and Neutrase enzymes caused a switch from the β-sheet organization of the proteins to α-helix structures. In conclusion, hazelnut meal may be a good source of bioactive and functional peptides. The control of its enzymatic hydrolysis, together with an appropriate pretreatment such as microfluidization, may be crucial to achieve the best suitable activity.