Selection of Enzymatic Treatments for Upcycling Lentil Hulls into Ingredients Rich in Oligosaccharides and Free Phenolics.

In this study, the comprehensive chemical characterization of red lentil hulls obtained from the industrial production of football and split lentils was described. The lentil hulls were rich in dietary fiber (78.43 g/100 g dry weight with an insoluble to soluble fiber ratio of 4:1) and polyphenols (49.3 mg GAE/g dry weight, of which 55% was bound phenolics), which revealed the suitability of this lentil by-product as a source of bioactive compounds with recognized antioxidant and prebiotic properties. The release of oligosaccharides and phenolic compounds was accomplished by enzymatic hydrolysis, microwave treatment and a combination of both technologies. The key role played by the selection of a suitable enzymatic preparation was highlighted to maximize the yield of bioactive compounds and the functional properties of the lentil hull hydrolysates. Out of seven commercial preparations, the one with the most potential for use in a commercial context was Pectinex® Ultra Tropical, which produced the highest yields of oligosaccharides (14 g/100 g lentil hull weight) and free phenolics (45.5 mg GAE/100 g lentil hull weight) and delivered a four-fold increase in terms of the original antioxidant activity. Finally, this enzyme was selected to analyze the effect of a microwave-assisted extraction pretreatment on the yield of enzymatic hydrolysis and the content of free phenolic compounds and oligosaccharides. The integrated microwave and enzymatic hydrolysis method, although it increased the solubilization yield of the lentil hulls (from 25% to 34%), it slightly decreased the content of oligosaccharides and proanthocyanidins and reduced the antioxidant activity. Therefore, the enzymatic hydrolysis treatment alone was more suitable for producing a lentil hull hydrolysate enriched in potential prebiotics and antioxidant compounds.

Lentil and Fava Bean With Contrasting Germination Kinetics: A Focus on Digestion of Proteins and Bioactivity of Resistant Peptides.

Germination offers advantages to improve legume protein digestibility as it disintegrates seed structure and hydrolyzes proteins and anti-nutrients. Seed permeability (related to polyphenol content of seed coats) is an important factor affecting the duration of seed germination and its impact on protein digestibility and bioactivity. The objective was to compare the effect of seed germination on protease activity, structure, and proteolysis of four selected legumes with contrasting seed coat polyphenol profiles (gray zero-tannin lentil [GZL], beluga lentil [BL], and dehulled red lentil [DL]; and zero tannin/low vicine-convicine fava bean [ZF]). Protein hydrolysis was characterized during germination and digestion with respect to proteins, peptides, and free amino acids (FAAs). In vitro antihypertensive and antioxidant activities of digests were investigated, and the peptidomic characterization [high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS)] and identification of bioactive fragments in intestinal digests were performed. Regardless of the seed type, germination increased protease activity and reduced the levels of phytic acid, trypsin inhibitors, and tannins (only in BL). A significant proteolysis of the 7S and 11S globulins and a concomitant increase of peptides and FAAs were observed in all sprouted legumes. Digestion kinetics in sprouts revealed a faster generation of FAAs and peptides than in dry seeds, with changes being more evident for DL, associated with a faster imbibition, germination, and sprout growth. In contrast, BL sprouts showed the lowest protein digestibility, likely due to a lower protease activity, seed structure disintegration, and higher anti-nutrient levels in comparison to GZL, DL, and ZF. Moreover, the digestion of sprouts resulted in a higher number of resistant peptides in DL and ZF that matched with previously reported bioactive sequences, suggesting a promising health potential of legume sprouts that was confirmed in vitro. The results suggested that the germination process improved protein digestibility and the health-promoting potential of lentil and fava bean proteins although these changes were more evident in DL due to its rapid imbibition, faster germination, and sprout development. This study will provide important information for either plant breeders to develop legume varieties with permeable seed coats or food producers that could use dehulled seeds for efficient production of sprouts as sustainable food sources of plant proteins with improved nutritional and healthy properties.

Enzyme Selection and Hydrolysis under Optimal Conditions Improved Phenolic Acid Solubility, and Antioxidant and Anti-Inflammatory Activities of Wheat Bran.

Valorization of wheat bran (WB) into new high-value products is of great interest within the framework of sustainability and circular economy. In the present study, we utilized a multi-step approach to extract nutraceutical compounds (phenolic acids) from WB and improved its antioxidant and anti-inflammatory properties through using sequential hydrothermal and enzymatic hydrolysis. Thirteen commercial glycosidases differing in their specific activity were screened and compared for hydrolytic efficiency to release monosaccharides, ferulic acid, and diferulic acid. Ultraflo XL was selected as the desired enzyme treatment on the basis of its higher WB solubilization, as well as its monosaccharide and phenolic acids yields. The relationships between better hydrolytic performance of Ultraflo XL and its particular activity profile were established. To determine the optimum conditions for Ultraflo XL treatment, we tested different factors (solvent pH, incubation temperature, and time) under 15 experiments. A multicomponent analysis (MCA), including central composite design, model fitness, regression coefficients, analysis of variance, 3D response curves, and desirability, was used for processing optimization. A beneficial effect of autoclave treatment on the release of phenolic compounds was also evidenced. The results of MCA showed involvement of linear, quadratic, and interactive effects of processing factors, although solvent pH was the main determinant factor, affecting enzymatic extraction of phenolics and bioactivity of hydrolysates. As compared to control WB, under optimized conditions (47 °C, pH = 4.4, and 20.8 h), WB hydrolysates showed 4.2, 1.5, 2, and 3 times higher content of ferulic acid (FA) and capacity to scavenge oxygen radicals, chelate transition metals, and inhibit monocyte chemoattractant protein-1 secretion in macrophages, respectively. These approaches could be applied for the sustainable utilization of WB, harnessing its nutraceutical potential.

Soluble Phenolic Composition Tailored by Germination Conditions Accompany Antioxidant and Anti-inflammatory Properties of Wheat.

Knowledge on the specific variation in the phenolic composition of wheat defined by germination conditions and its relationship with antioxidant and anti-inflammatory properties of sprouts would be useful to improve the functional value of wheat-derived products. Variation in soluble phenolic composition, antioxidant and anti-inflammatory potential of wheat was examined in a range of germination temperature (12-21 °C) and time (1-7 d). Response surface methodology was applied for building lineal and quadratic models to find optimal germination conditions to improve nutraceutical value of wheat sprouts using the desirability (D) function. Phenolics were determined by HPLC-DAD-ESI-MS. In vitro biochemical methods and lipopolysaccharide stimulated RAW264.7 macrophages were used to determine antiradical and anti-inflammatory activities of wheat sprouts. Accumulation of soluble phenolic acids, flavone C-glycosides and lignans in sprouts was positively influenced by germination temperature and time. Increased concentration of individual polyphenols was directly associated with improved ability of sprouts for radical scavenging and reduction of tumor necrosis factor α and interleukin 6 in macrophages. Optimal desirability (D = 0.89) for improved nutraceutical value of wheat sprouts was achieved at 21 °C for 7 d. This information would be useful for food industry aiming at producing wheat-based products with better nutritional and healthy properties.

Pilot-scale produced fermented lentil protects against t-BHP-triggered oxidative stress by activation of Nrf2 dependent on SAPK/JNK phosphorylation.

Fermented lentil (FL) produced using L. plantarum and Savinase in alkaline conditions relieves metabolic alterations and oxidative stress in Zucker rats with metabolic syndrome. Here, we investigated the effect of up scaling the fermentation process on chemical composition and biological activity of FL. Moreover, we studied the molecular mechanisms by which FL exert a cytoprotective effect against oxidative stress in tert-butyl hydroperoxide (t-BHP)-challenged RAW264.7 macrophages. Up-scale production reduced overall biological effectiveness of FL with the exception of inhibition of intracellular ROS generation. FL prevented t-BHP-induced cytotoxicity and intracellular accumulation of reactive oxygen species through activation of catalase expression via SAPK/JNK phosphorylation and Nrf2 nuclear translocation. Different oligopeptides, phenolic acids and flavonols were identified as contributors of the observed effects. To the best of our knowledge, we reported for the first time that FL attenuates oxidative stress cellular damage via activation of SAPK/JNK phosphorylation, Nrf2 nuclear translocation and antioxidant enzymes expression.

pH-controlled fermentation in mild alkaline conditions enhances bioactive compounds and functional features of lentil to ameliorate metabolic disturbances.

Lentil fermentation has a promising potential as a strategy for development of multifunctional ingredients targeting metabolic syndrome (MetS). Response surface methodology was applied to optimize lentil fermentation and study its effects on generation of peptides, soluble phenolics and bioactivities. Fermentation using Lactobacillus plantarum and Savinase® 16 L was carried out at different pH (6.5-8.5) and times (5.5-30 h). Analysis of variance was performed to evaluate linear, quadratic and interaction effects between fermentation parameters. pH positively affected peptides, soluble phenolic compounds and antioxidant activity whereas a negative impact on lipase inhibitory activity was observed (p < .0001). Time showed positive effect on proteolysis and negatively affected angiotensin I-converting enzyme inhibitory activity of fermented lentil (p < .0001). Multivariate optimization led to high levels of peptides, soluble phenolics and bioactivity of fermented lentil at pH 8.5 and 11.6 h. In conclusion, this study might contribute to the development of functional ingredients from lentil for MetS management.

Individual contributions of Savinase and Lactobacillus plantarum to lentil functionalization during alkaline pH-controlled fermentation.

Legumes offer the possibility to develop multifunctional foods with benefits for metabolic syndrome. Our objective was to study the effect of alkaline fermentation by Lactobacillus plantarum and Savinase (FLPS) as well the individual effects of both processes on peptides, phenolics and bioactivity of lentil. FLPS increased peptides and some flavonoids and enhanced antioxidant activity, inhibition of angiotensin I-converting enzyme (ACE) and intestinal maltase activities of lentil soluble fraction. Savinase contributed to peptide release, ACE inhibitory and antioxidant activities of lentil soluble fraction. L. plantarum affected to phenolic composition, α-glucosidase and lipase inhibitory activities. Mass spectrometry analysis of the most active fermented lentil subfraction allowed the identification of the main bioactive compounds. Gastrointestinal digestion of fermented lentil increased bioaccessibility of peptides and phenolics as well as antioxidant activity. FLPS enhanced the overall healthy potential of lentil offering the possibility of its use as strategy for lentil functionalization.