Digestion Studies Research Articles

Gastrointestinal Fate and Fatty Acid Release of Pickering Emulsions Stabilized by Mixtures of Plant Protein Microgels + Cellulose Particles: an In Vitro Static Digestion Study

The present study aims to investigate the in vitro intestinal digestion fate of Pickering emulsions with complex dual particle interfaces. Pickering oil-in-water emulsions (PPM-E) stabilized by plant (pea) protein-based microgels (PPM), as well as PPM-E where the interface was additionally covered by cellulose nanocrystals (CNC), were designed at acidic pH (pH 3.0). The gastrointestinal fate of the PPM-E and free fatty acid (FFA) release, was tested via the INFOGEST static in vitro digestion model and data was fitted using theoretical models. Lipid digestion was also monitored using lipase alone bypassing the gastric phase to understand the impact of proteolysis on FFA release. Coalescence was observed in the PPM-stabilized emulsions in the gastric phase, but not in those co-stabilized by CNC. However, coalescence occurred during the intestinal digestion stage, irrespective of the CNC concentration added (1–3 wt % CNC). The presence of CNC lowered the lipolysis kinetics but raised the extent of FFA release as compared to in its absence (p < 0.05), due to lower levels of gastric coalescence, i.e., a higher interfacial area. The trends were similar when just lipase was added with no prior gastric phase, although the extent and rate of FFA release was reduced in all emulsions, highlighting the importance of prior proteolysis in lipolysis of such systems. In summary, an electrostatically self-assembled interfacial structure of two types of oppositely-charged particles (at gastric pH) might be a useful strategy to enable enhanced delivery of lipophilic compounds that require protection in the stomach but release in the intestines.

Can machine learning algorithms perform better than multiple linear regression in predicting nitrogen excretion from lactating dairy cows

This study aims to compare the performance of multiple linear regression and machine learning algorithms for predicting manure nitrogen excretion in lactating dairy cows, and to develop new machine learning prediction models for MN excretion. Dataset used were collated from 43 total diet digestibility studies with 951 lactating dairy cows. Prediction models for MN were developed and evaluated using MLR technique and three machine learning algorithms, artificial neural networks, random forest regression and support vector regression. The ANN model produced a lower RMSE and a higher CCC, compared to the MLR, RFR and SVR model, in the tenfold cross validation. Meanwhile, a hybrid knowledge-based and data-driven approach was developed and implemented to selecting features in this study. Results showed that the performance of ANN models were greatly improved by the turning process of selection of features and learning algorithms. The proposed new ANN models for prediction of MN were developed using nitrogen intake as the primary predictor. Alternative models were also developed based on live weight and milk yield for use in the condition where nitrogen intake data are not available (e.g., in some commercial farms). These new models provide benchmark information for prediction and mitigation of nitrogen excretion under typical dairy production conditions managed within grassland-based dairy systems.

Performance indicators of sheep fed rice straw supplemented with browse leaves

The use of browse leaves as a protein source can help ruminants cope with adverse nutritional stress under unpredictable climatic conditions. The objective of this study was to determine feed intake, digestibility, metabolisable energy intake, weight gain and feed conversion efficiency of sheep fed untreated rice straw supplemented with browse leaves. Four forest type rams with an average weight of 27.75± 0.89 kg (2 years old) and in a replicated 4 x 4 Latin square design were used in the digestibility study. Twelve ram lambs of average weight 13.2 kg ± 0.05 kg were assigned to the experimental diets randomly for 12 weeks in the growth study in a completely randomized design. Animals were fed four diets namely: Untreated rice straw (URS) + Albizzia lebbek (AL) (Control), URS + Moringa oleifera (MO), URS + Ficus exasperata (FE) and URS + Spondias mombin (SM). The dietary treatment influenced (p&lt;0.05) the digestible organic matter in dry matter (DOMD), maintenance energy requirement (MEm), metabolisable energy intake (MEI) and ratio of metabolisable energy intake to maintenance energy requirement (MEI: MEm). The DOMD, MEm, MEI and MEI: MEm were in the range of 965-983 g/kgDM, 3.61-5.36 MJ/d, 9.51-15.8 MJ/d and 2.63-3.38 respectively. The total intake of browse and straw ranged from 428.71 to 487.14 g/d. The average daily gain ranged from 7.14 to 20.24 g/d. The animals fed URS+FE recorded the highest average daily gain (p&lt;0.05) while the animals fed URS+AL recorded the lowest average daily gain (p&lt;0.05). Feed conversion efficiency ranged from 25.97 to 71.45 kg feed/ kg gain. The sheep fed URS+FE were the most efficient (p&lt;0.05) and those fed URS+AL, the least efficient (p&lt;0.05). Supplementation of browse leaves to sheep using untreated rice straw as a basal diet improved digestibility with moderate weight gains. These browse leaves (AL, FE, MO and SM) can be used to supplement poor quality ruminant diets for improved performance particularly during periods of feed scarcity. Key words: Digestible organic matter in dry matter, metabolisable energy, weight gain

Assessing the feasibility of particle size reduction and fermentation as pre-processing techniques to utilize enzyme-treated feather meal in zero fish meal diets for Nile tilapia (Oreochromis niloticus)

In this study, a growth trial and digestibility assays were conducted to evaluate the applicability of particle size reduction and fermentation as pre-processing techniques to treat enzyme-treated feather meal (ETF) for zero fish meal diet of Nile tilapia (Oreochromis niloticus). According to particle size, ETF was mechanically sieved and separated into three different categories (un-sieved (EFM), particles < 850 µ (EFM850), particles < 425 µ (EFM425)) while a portion of each category was separately fermented for 24 h using Baker’s yeast to produce fermented ingredients, un-sieved (FEFM), fermented 850 µ (FEFM850) and fermented 425 µ (FEFM425). Seven isoproteic and isoenergetic diets were prepared including a control diet with 10 % fishmeal. The fishmeal component of the control diet was completely replaced by one of the six types of EFM in test diets. Sex-reversed male Nile tilapia (~ 6 g initial weight) fingerlings were stocked (20 fish per tank) in circular concrete tanks (200 L). Each treatment with three replicates was randomly allocated into 21 tanks using a complete randomized design. Fish were hand-fed twice a day to near satiety for 56 days. In-vivo digestibility study and in-vitro protein hydrolysis assays of six EFM types were evaluated by mixing 30 % of test ingredients and 70 % of reference diet having 0.5 % of chromic oxide. In vitro assay was performed by using crude enzymes extracted from Nile tilapia. Results of the growth trial revealed that the final mean weight, daily weight gain, and % specific growth rate of fish fed EFM425 and FEFM were significantly higher than that of other treatments (p < 0.05) while FEFM425 showed significantly lowest growth performances. Feed intake of fish in FEFM treatment was significantly higher than that of control. The effects of different dietary treatments on survival rate and feed utilization efficiency were not statistically different (p > 0.05). The highest protein (77 %) and dry matter (68 %) digestibility were observed for EFM425 and FEFM while the dry matter digestibility positively correlated to the daily weight gain (R2 = 0.80). Based on growth performance, feed utilization efficiencies, and digestibility, EFM425 and FEFM were best among tested treatments. But in practice, particle size reduction is more convenient than fermentation. It was concluded that fish meal components of Nile tilapia diets can be replaced by EFM by reducing their particle size up to 425 µ.

Influences of specific surfactant structures on biohydrogen production from oily wastewater in batch and continuous anaerobic dark fermentation

Residual oil in palm oil mill effluent (POME) poses difficulties in its treatment chain. Non-ionic surfactants containing different hydrophobic tail structures and their optimal concentrations were evaluated for effectiveness in biohydrogen production. By adding the surfactants at their critical micelle concentration in synthetic oily wastewater, the maximal H2 yield was increased by 2.2 and 3.5 times for Triton X-100 and Tergitol 15-S-9, respectively, compared to the control. Using real POME, the supplemental Tergitol 15-S-9 resulted in a 56.4 % improvement in H2 production. For continuous digestion studies, pure POME and Tergitol 15-S-9 supplemented POME (sPOME) were fed to thermophilic anaerobic sequencing batch reactors (ASBRs) under hydraulic retention time (HRT) of 32–12.5 days. Optimally at HRT 19 days, H2 content in the biogas from sPOME-fed ASBR was noticeably higher, which gave a superior yield of 203.4 mLH2/gCODremoved (+15 %).

The swallowing threshold and starch hydrolysis of cooked rice with different moisture contents for human mastication

Swallowing threshold is a critical parameter that marks the condition of food after mastication in the human mouth being ready to be swallowed. In the current study, a new aspect was investigated in which the food boluses from cooked rice with three moisture contents (52%, 63% and 73% on a wet basis) were masticated and collected just before swallowing by a group of twelve voluntary participants. Both mechanical/textural properties and physicochemical characteristics of the cooked rice and their boluses were investigated. The results show that the oral duration of the cooked rice was positively associated with rice hardness, but negatively correlated with the moisture content of rice boluses. After chewing, the textural properties except cohesiveness and adhesiveness varied little among the rice bolus samples. A significant decrease in the textural parameters was shown for the cooked rice with a low (52%) and middle (63%) moisture content after mastication. In contrast, the decrease was insignificant for the cooked rice having the highest moisture content (73%). Consistently, a negative correlation between the hardness of cooked rice and the amount of soluble reducing sugar in the rice boluses was presented. The salivary impregnation and the particle size distribution of the rice boluses at the swallowing threshold were independent on rice physics (i.e., initial moisture content, texture) and oral physiology. In addition, due to the high efficiency of salivary α-amylase, the starch in cooked rice could be hydrolyzed as much as one-third during oral digestion. The present study suggests that the initial moisture content of cooked rice and mastication conditions such as the presence of α-amylase and salivary impregnation could influence the physicochemical properties of rice boluses at the swallowing threshold. These factors should be carefully considered in future in vitro digestion studies of carbohydrate-based food products.

Microencapsulation of de‐glycosylated mulberry ( Morus alba L.) fruit extract through double‐layered multiple emulsions of pectic polysaccharide extracted from Ulmus davidiana and soy protein isolate

Our objectives were to (1) encapsulate de-glycosylated mulberry fruit extract (dg-MFE) through double-layered multiple emulsions of pectic polysaccharide from Ulmus davidiana (UDP) and soy protein isolate (SPI) by spray dryer and (2) investigate the physicochemical, storage, and in vitro digestibility properties of the encapsulated powders. Four different concentrations of UDP (0, 0.5, 1.0, 1.5, and 2.0 g UDP per 3.0 g SPI) were prepared for microencapsulation of dg-MFE. HR FE-SEM morphology of encapsulated powders became spherical with an increase in the concentrations of UDP. Due to the production of thicker layers by the formation of electrostatic interactions between small positively charged groups of SPI and negatively charged groups of UDP, particle sizes and storage stability of the encapsulated powders prepared by SPI-UDP were improved. In vitro digestion study indicated that the release of dg-MFE was effectively controlled by a protective coating of SPI-UDP under the simulated gastric and intestinal fluid. Novelty impact statement This study was investigated to enhance the stability of de-glycosylated mulberry (Morus alba L.) fruit extract during the storage and digestion process and to develop a slow-release targeted delivery system to the colon. Based on HR FE-SEM analysis, encapsulation efficiency, storage stability, and simulated gastrointestinal digestion analysis, these results demonstrated that the encapsulated powders prepared by soy protein isolate-Ulmus davidiana complexes were found to be better coating materials for microencapsulation of de-glycosylated mulberry fruit extract than those prepared by only soy protein isolate. Therefore, this study provides a promising technology to protect bioactive compounds during storage and passing through the upper gastrointestinal tract.

In vitro Digestibility Study of Starch Complexed with Different Guest Molecules

AbstractDigestibility of starch is an essential issue in food science studies due to its close relationship with human health. Most common starchy foods contain rapidly digestible starch, which can lead to chronic diseases, including type II diabetes. Heat–moisture treated potato starch (HPS) followed by inclusion complexation with guest molecules is prepared to improve starch's physicochemical properties, resulting in reduced digestibility. The guest molecules used in this study are linoleic acid (LA), stearic acid (SA), and sodium stearate (SS). The in vitro digestibility of the modified starches over time compared to native starch after gelatinization at 95 °C is examined. The starch complexed with SS results in the least amount of rapidly digestible starch (RDS), followed by LA and SA, consecutively. Furthermore, the starch‐SS complexes are the most slowly digestible starch (SDS) and included the highest amount of resistant starch (RS), followed by LA and SA. Sodium stearate results in the highest transformation of RDS to be SDS and RS. Thermal analysis data and microscopy images support the digestion results.

Field pea can replace soybean meal-corn mixtures in the fattening concentrate of young bulls improving the digestibility

The inclusion of pea (Pisum sativum) in the fattening concentrate at 0%, 15%, 30%, and 45% as a replacement for soybean meal and corn was evaluated on in vitro and in vivo digestibility studies of young Parda de Montaña bulls. In the in vitro trial, gas production was determined with an Ankom system for 48 h. The 30%pea and 45%pea concentrates increased the organic matter (OM) degradability, the ammonia-N content and the ratio of acetic:propionic, with no effect on gas production, final ruminal pH and total volatile fatty acid production. In the in vivo assay, 4 young bulls (initial weight 251 ± 4 kg) received restricted amounts of concentrates plus straw during 4 consecutive experimental periods. No differences in intake were observed and 30%pea and 45%pea had higher digestibility of crude protein (CP), and OM than the rest of treatments. The nitrogen intake increased linearly with the inclusion of pea with similar nitrogen urinary and faecal excretions, and the nitrogen retained was greater in 30%pea and 45%pea than the rest of treatments. The plasma concentrations of IGF-1, total protein, β-hydroxybutyrate and urea at the beginning and at the end of each period were not affected by the inclusion of pea. In conclusion, the total replacement of soybean-corn mixtures by pea in the fattening concentrate of bulls could be recommended as it improved the CP digestibility and nitrogen retention.

Biological depolymerization of lignin using laccase harvested from the autochthonous fungus Schizophyllum commune employing various production methods and its efficacy in augmenting in vitro digestibility in ruminants

A laccase-producing hyper performer, Schizophyllum commune, a white-rot fungus, was evaluated for its ability to selectively degrade lignin of diverse crop residues in vitro. Relative analysis of crop residue treatment using laccase obtained from immobilized cells demonstrated degradation of 30–40% in finger millet straw and sorghum stover, 27–32% in paddy straw, 21% in wheat straw, and 26% in maize straw, while 20% lignin degradation was observed when purified and recombinant laccase was used. Further investigations into in vitro dry matter digestibility studies gave promising results recording digestibility of 54–59% in finger millet straw 33–36% in paddy straw and wheat straw, 16% in maize straw for laccase obtained from cell immobilization method, whereas 14% digestibility was observed when purified and recombinant laccase was used. Sorghum stover recorded digestibility of 13–15% across all straws treated with laccase. The results obtained elucidated the positive influence of laccase treatment on lignin degradation and in vitro dry matter digestibility. The present research gave encouraging figures confirming the production of laccase using the cell immobilization method to be an efficient production method commensurate with purified and recombinant laccase under conditions of submerged cultivation, proclaiming a cost-effective, environmentally safe green technology for effectual lignin depolymerization.

Two-Phase Anaerobic Digestion of Corn Steep Liquor in Pilot Scale Biogas Plant with Automatic Control System with Simultaneous Hydrogen and Methane Production

Experimental studies of two-phase anaerobic digestion of corn steep liquor in semi-continuous automatic and semi-automatic modes of operation of a cascade of two anaerobic bioreactors with monitoring and control systems were performed. Corn steep liquor—a waste product from the process of treating corn grain for starch extraction—was used as a substrate in the process of anaerobic digestion with simultaneous hydrogen and methane production. The daily yields of biohydrogen in bioreactor 1 of the cascade (with a working volume of 8 dm3) are variable. In good operation, they are in the range of 0.7 to 1.0 L of biogas from a 1 dm3 working volume of the bioreactor, and the optimal pH is in the range of 5.0–5.5. The concentration of hydrogen in the biogas from the hydrogen bioreactor 1 is in the range of 14–34.7%. The daily yields of biomethane in bioreactor 2 of the cascade (with a working volume of 80 dm3) vary in the range 0.4 to 0.85 L of biogas from a 1 dm3 working volume of the bioreactor, and the concentration of methane in the biogas from bioreactor 2 is high and remains practically constant (in the range 65–69%). At a dilution rate of 0.4 day−1 and an organic loading rate of 20 gL for bioreactor 1, respectively, and a dilution rate of 0.05 day−1 for bioreactor 2, the best results were obtained. The computer control system is presented. Some energetical considerations were discussed.

In vitro gastrointestinal digestion studies on total phenols, flavonoids, anti-oxidant activity and vitamin C in freeze-dried vegetable powders.

In the present research study, the impact of digestion process on the levels of total phenols, flavonoids, vitamin C as well as anti-oxidant activity in freeze dried powders of mustard greens (MG) and roselle leaves (RL) was investigated. In addition, physicochemical and functional properties of MG and RL samples also evaluated. The digestion of freeze-dried vegetable powders was achieved through in vitro digestive procedure using various enzymes. From the study, it was observed that the digestion process increased the availability of phenols in both powders, where the digested vegetable powders possessed higher levels of total phenols and flavonoids. In contrast, the levels of vitamin C and anti-oxidant activity of vegetable powders (MG & RL) was found to be decreased minimally. Our research study suggests that in vitro digestion could enhance the TPC and TFC in mustard greens and roselle leaves. Therefore, MG and RL can be considered as a functional ingredient in the development of new products with better nutritional and functional characteristics. Further, the data on the physicochemical, functional and bioactive compounds in MG and RL may be used as reference for the enhancement of quality of products developed from MG and RL.

Composition and Adaptation of the Enteric Neural System in Laboratory Rodents: A Cellular Overview

The enteric nervous system (ENS) is a neuron network present in the digestive system. Intestinal tract anatomic differences and cellular composition in different animals can help with interaction with environmental comprehension, which is a pertinent theme in molecular and cellular neurophysiology. In mammals, ENS is not the same in all species; rodents, generally, are great models for digestive tract adaptation study in physiologic process and environmental adaptation interpretation. This study is a narrative overview that describes morphological and cellular composition characterization in rodent neural enteric systems. Interstitial Cajal cells structural characteristics; ENS embryonic cell; system adaptation mediated by fasting, acute and chronic starve; gestation and lactation; temperature and diet; parasitism and rodent caloric restriction were aborded. Seasonal or transitory changes in intestine size probably occur when connected to food quality than its availability. Changes in female intestine size are reversible and periodic, increasing during lactation rodent as an attractive model for digestive flexibility study in the intestine size adjustment area. Enteric nervous system neuron morphological classification is presented, according to digestive tract localization and animal species. In conclusion, a significant change in intestinal mass and length in different rodent species can implicate intestinal motility during and after intestinal tract injury.

Biocompatible Cationic Lipoamino Acids as Counterions for Oral Administration of API-Ionic Liquids

PurposeThe use of ionic liquids (ILs) in drug delivery has focused attention on non-toxic IL counterions. Cationic lipids can be used to form ILs with weakly acidic drugs to enhance drug loading in lipid-based formulations (LBFs). However, cationic lipids are typically toxic. Here we explore the use of lipoaminoacids (LAAs) as cationic IL counterions that degrade or digest in vivo to non-toxic components.MethodsLAAs were synthesised via esterification of amino acids with fatty alcohols to produce potentially digestible cationic LAAs. The LAAs were employed to form ILs with tolfenamic acid (Tol) and the Tol ILs loaded into LBF and examined in vitro and in vivo.ResultsCationic LAAs complexed with Tol to generate lipophilic Tol ILs with high drug loading in LBFs. Assessment of the LAA under simulated digestion conditions revealed that they were susceptible to enzymatic degradation under intestinal conditions, forming biocompatible FAs and amino acids. In vitro dispersion and digestion studies of Tol ILs revealed that formulations containing digestible Tol ILs were able to maintain drug dispersion and solubilisation whilst the LAA were breaking down under digesting conditions. Finally, in vivo oral bioavailability studies demonstrated that oral delivery of a LBF containing a Tol IL comprising a digestible cationic lipid counterion was able to successfully support effective oral delivery of Tol.ConclusionsDigestible LAA cationic lipids are potential IL counterions for weakly acidic drug molecules and digest in situ to form non-toxic breakdown products.

Kinetic investigations into the effect of inoculum to substrate ratio on batch anaerobic digestion of simulated food waste

This anaerobic digestion (AD) study investigated the effect of inoculum to substrate ratio (ISR 4.00 to 0.25) on viability of methanogenesis using simulated food waste as substrate. Given the complexity of the AD process, this study considered the interdependency of AD parameters and their effect on biogas production, as the digestion progressed. Maximum methane production was between ISR 2.00 (139 ± 10 ml CH4/g VS added) and 1.00 (152 ± 12 ml CH4/g VS added); further decreases in ISR were found to result in system acidification. Under acidogenic conditions (ISR≤0.5) pH and the volatile fatty acid (VFA) profile were found to be strongly dependent on the ISR. In contrast to ISR 0.25, ISR 0.50 showed reverse beta oxidation, which resulted in increased concentrations of medium chain VFAs over the digestion period. Maximum total VFA (TVFA) concentrations that the system could survive with reversible acidification (ISR 1.00) was found to be 17.52 ± 0.02 g/l, whereas the maximum TVFA production was found to be 29.25 ± 0.73 g/l for ISR 0.50. Uniquely, this study also reports up to 55% anaerobic degradation of lignin in acidified reactors with ISR 0.25, which based on existing literature, points towards the involvement of specific bacterial strains.

Making a meal out of bugs

Making a meal out of bugs

Effects of Multi-Ingredient Nutritional Drink Including Mulberry Leaf Extract (MLE) on Postprandial Glycemic and Appetite Responses in Healthy Chinese Adults

ObjectivesOur study aimed to evaluate the impact of adding MLE to a nutritional drink containing protein, fat, carbohydrate (maltodextrin) on maltodextrin digestion in-vitro and postprandial glucose and appetite responses in healthy Chinese adults. MethodsTwo randomized cross-over trials were conducted in healthy Chinese adults (20–40 y; 19–24 kg/m2) measuring glucose, hunger and satiety responses. Visual Analog Scale (VAS) was used to evaluate hunger and satiety. In trial 1, participants (n = 12) received either 25 g anhydrous glucose powder mixed in water or the tested nutritional drink (25 g carbohydrate and MLE). Blood glucose was tested 5 min before and at 0, 15, 30, 45, 60, 90, and 120 min after sample intake. In trial 2, participants (n = 10) received either the MLE nutritional drink (∼200 kcal) or a reference food with similar energy and macronutrient composition but no MLE. VAS results were collected at 0, 30, 60, 90 and 120 min after sample intake. An in-vitro digestion study was conducted using 3 different ratios of MLE and maltodextrin to explore the effects of MLE on maltodextrin digestion. ResultsBaseline glucose levels were similar between the two groups. Postprandial glucose was significantly lower in the test group at 15 min (5.9 ± 0.3 mmol/L vs 7.4 ± 0.4 mmol/L), 30 min (5.9 ± 0.7 mmol/L vs 8.3 ± 0.7 mmol/L) and 45 min (5.7 ± 0.6 mmol/L vs 7.0 ± 0.9 mmol/L) compared to reference group. Glucose iAUC0-120 min was also significantly lower (64.6 ± 11.1 mmol/L x min vs 135.0 ± 14.5 mmol/L x min) in the test group. In trial 2, VAS desire to eat iAUC0-120 min, was significantly lower (–494.9 ± 80.97 cm x min vs –307.4 ± 52.05 cm x min) in MLE test group, but other satiety parameters were similar between the two groups. Maltodextrin hydrolysis rate (in-vitro digestion study) iAUC0-180 min was significantly inhibited by MLE (P < 0.05) at ratio of 20:1 and 10:1 (Maltodextrin: MLE). ConclusionsConsumption of tested nutritional drink with optimized MLE dose produced a significant lower postprandial glucose response and meets the ISO requirements to be claimed low GI. Moreover, the satiety (as measured by desire to eat using VAS) is higher than the reference food with similar energy and macronutrient composition without MLE. Therefore, adding MLE into nutritional drink lowers GI, reduces postprandial glucose response and may promote satiety. Funding SourcesMary Kay, Inc.

In vitro gastrointestinal digestion study and identification of novel angiotensin i-converting enzyme inhibitory peptide from broccoli (brassica oleracea)

Due to the side effects of synthetic ACE inhibitors like captopril used for the treatment of hypertension, ACE inhibitory peptides derived from natural sources have attracted increasing attention in recent years. The aim of this work was to screen the vegetable with the highest angiotensin I-converting enzyme (ACE) inhibitory activity from 50 kinds of vegetables by using three different extraction methods, and to purify and identify the novel peptides from broccoli protein hydrolysates and evaluated the ACE inhibitory activity in vitro. Through centrifugation, ultrafltration, gel chromatography and high performance liquid chromatography (HPLC), the fraction BHs-IV-I-IV of the enzyme hydrolysate of broccoli with 100% ACE inhibitory activity was obtained. The novel ACE inhibitory peptide (KSVLLKF, KF-7) was identifed from fraction BHs-IV-I-IV by ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS). ACE inhibition rate of 0.05 mg of KF-7 reached 42.86%, whereas 12.48 mg of pepsin hydrolysate of broccoli crude extract only exhibited 55.29% of ACE inhibition rate, indicating the low content of KF-7 in the protein hydrolysates of broccoli. These results suggested that KF-7 has a potential application in functional foods/pharmaceutical agents against hypertension and protein from broccoli may constitute a potential antihypertensive peptide source.

Effects of chemical pretreatments on material solubilization of Areca catechu L. husk: Digestion, biodegradability, and kinetic studies for biogas yield

This study aimed to understand the pretreatment-aided anaerobic digestion of lignocellulosic residues and to assess the substrate solubilization capacity of pretreatment processes. We evaluated the feasibility of biogas production using chemically pretreated Areca catechu L. (Arecanut husk, AH). AH was pretreated for 24h at two different temperatures—25 °C and 90 °C with four different chemicals viz. H2SO4 (acidic), NaOH (alkaline), H2O2 (oxidative), and ethanol in 1% H2SO4 (organosolv) under each temperature. AH solubilization assessment included analyses of parameters such as volatile solids to total solids (VS:TS) ratio, soluble chemical oxygen demand, total phenolic content, and biomass composition. Alkaline pretreatment of AH at 90 °C resulted in the maximum biogas yield of 683.89mL/gVS, which was 2.3 times more than that obtained using raw AH without pretreatment. Methane content of biogas produced using AH pretreated with 2–10% of NaOH was found to be between 71.53% and 75.06%; methane content of biogas using raw AH was 62.31%. In order to describe the AH degradation patterns, biogas production potential from pretreated AH was evaluated using bacterial kinetic growth models (First-order exponential, logistic, transference, and modified Gompertz models). The modified Gompertz and logistic models (correlation coefficient >0.99) were found to have the best fit of all kinetic models for the cumulative experimental biogas curve. We formulated a multiple linear regression equation depicting the biodegradability index (BI) as a technical tool to determine biomethane production; BI is represented as a function of biomass composition (cellulose, hemicellulose, and lignin), with a high correlation (>0.95). Based on our analyses of AH pretreatment and substrate utilization for biogas production, we propose that the biochemical composition of lignocellulosic residues should be carefully considered to ensure their biodegradability when subjected to anaerobic digestion.

Both alkyl chain length and V-amylose structure affect the structural and digestive stability of amylose-alkylresorcinols inclusion complexes

Alkylresorcinols (ARs) are a group of bioactive phenolic lipids and mostly concentrated in the bran of whole grains. In this study, the influences of alkyl chain length of ARs and V-amylose structure on the stability of V-amylose-ARs inclusion complexes were characterized. On the one hand, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and in vitro digestion studies of complexes showed that the crystallinity, thermo-stability, and digestion resistance of V-amylose-ARs inclusion complexes increased with increasing alkyl chain length of ARs. On the other hand, V6-amylose-ARs inclusion complexes displayed the strongest thermostability, the highest crystallinity, and the lowest digestibility compared to V7-amylose-ARs inclusion complexes and V8-amylose-ARs inclusion complexes. It could be concluded that both the helical structure of hydrated V6-amylose and ARs with longer alkyl chain stabilized the structure and stability of the inclusion complexes. This work could pave a way to develop bioactive cereal foods with high bioaccessibility of ARs.