Higher Digestibility Research Articles

Metagenomes and metagenome-assembled genomes from a sequentially fed anaerobic digester treating solid organic municipal waste.

We present a data set of four metagenomes and 281 metagenome-assembled genomes describing the microbial community of a laboratory-scale high solids anaerobic digester. Our objective was to obtain information on the coding potential of the microbial community and draft genomes of the most abundant organisms in the digester.

Feasibility of Tenebrio molitor larvae protein to partially replace lean meat in the processing of hybrid frankfurters: Perspectives on quality profiles and in vitro digestibility

The aim of this study was to investigate the effect of replacing different amounts (5 %, 10 %, 15 %, 20 % and 25 %) of lean meat with Tenebrio molitor larvae protein (TMLP) on the quality profiles of hybrid frankfurters. The results showed that there were no obvious differences in moisture, protein or fat content of all the hybrid frankfurters (P > 0.05), only a higher substitution rate (from 10 % to 25 %) resulted in a higher ash content than the control group (P < 0.05). With the increasing replacement rate (5 %, 10 % and 15 %), the cooking loss of the hybrid frankfurters showed the similar effects as the control group (P > 0.05), whereas the higher replacement rates of 20 % and 25 % obviously decreased the emulsion stability of the hybrid frankfurters. Moreover, with lower substitution rate (5 %, 10 % and 15 %) there were no significant differences in cooking loss between the hybrid frankfurters and the control group (P > 0.05), whereas the higher substitution rates (20 % and 25 %) obviously increased the cooking loss of the hybrid frankfurters (P < 0.05). Meanwhile, as the level of substitution increased, the hybrid frankfurters had higher digestibility, poorer texture than the standard frankfurters, as well as the rheological behaviour of hybrid meat batters (P < 0.05). The results showed that a moderate level (15 %) of TMLP was used to replace lean pork could be potentially and successfully be used to produce hybrid frankfurters.

Anaerobic Co-Digestion of Vinasse and Pentose Liquor and the Role of Micronutrients in Methane Production within Sugarcane Biorefineries

Anaerobic digestion (AD) of residues from integrated first- and second-generation ethanol (1G2G) biorefineries is a sustainable method for energy recovery through biogas production. This study evaluated the co-digestion of 1G vinasse, 2G vinasse and pentose liquor (from the pretreatment of sugarcane bagasse for 2G ethanol production) compared to individual digestions using biochemical methane potential (BMP) assays. The results showed some “key” micronutrients from the substrates that affected methane (CH4) production, while their balance provided by co-digestion achieved high digestibility (95%). High iron (Fe) and nickel (Ni) concentrations, in addition to furfural (0.33 g L−1) in pentose liquor seemed to decrease its CH4 production potential. Despite these adverse effects observed in mono-digestion, co-digestion was beneficial for this substrate, increasing digestibility (52%) and BMP (118%). The highest BMP was observed in vinasse 2G (631 ± 6 NmL CH4 gTVS−1), with no significant difference compared to the adjusted modified Gompertz model (624 ± 10 NmL CH4 gTVS−1). The co-digestion system also presented the highest specific CH4 production rate (20 ± 1 NmL CH4 gTVS−1day−1) and shortened the lag phase by 19% compared to the AD of isolated 1G vinasse with the second lowest BMP value (494 ± 11 NmL CH4 gTVS−1).

Microalgae suspension as a source of n-3 long-chain PUFA in feed for Atlantic Salmon (Salmo salar L) – Technical constraints and nutritional quality

The aim of this research was to study possible inclusion levels of AlgaPrime™ DHA LS microalgae (Schizochytrium sp.) plant oil suspension in feed mixes prior to extrusion and in the post drying vacuum coating step and evaluate microalgae digestibility in Atlantic salmon (Salmo salar L). In the technical evaluation, physical quality, expansion, and microstructure parameters were studied for AlgaPrime™ DHA LS inclusion in fishmeal and plant-based diets prior to extrusion. A target lipid level of 361 g/kg DM was achieved for all feeds. High physical quality and water stability were measured and mixture design models with R2 in the range of 0.950 to 0.999 (P < 0.001) were established for specific mechanical energy (SME), apparent dough viscosity in the extruder die (Vdie), expansion, and microstructure parameters. Addition of AlgaPrime™ DHA LS resulted in a feed mix lipid level in the range of 27 to 204 g/kg and was the main contributor for the observed variation in this study. Commercially, the most interesting feed was the centroid point with a feed mix lipid content of 92 g/kg. This equals an AlgaPrime™ DHA LS content of 48 g/kg in the final feed. Alternatively, the AlgaPrime™ DHA LS can be added in the vacuum coating process. In this study the pellet pores size distribution allowed high amount of microalgae suspension to be absorbed (50% of total oil) with no significant impact on oil leakage. Based on the findings in the technical trial, 4 diets were produced for the fish experiment; 1) control feed with a 1:1 fish oil and rapeseed oil mixture, 2) a feed where the oil mixture was partly replaced by 100 g/kg AlgaPrime™ DHA LS prior to extrusion, 3) a feed where 100 g/kg of oil mixture were replaced in the vacuum coating step by 100 g/kg AlgaPrime™ DHA LS and 4) where 100 g/kg oil mixture was replaced both prior to extrusion and in the vacuum coating step by AlgaPrime™ DHA LS. All diets showed high nutrient digestibility in Atlantic salmon, also for the saturated fatty acids. This documents no need for extra cell wall rupture for the microalgae suspension prior to extrusion or vacuum coating. Lower content of tri-saturated triacylglycerols than reported in previous Schizochytrium biomasses have limited the negative effects on the digestibility of saturated fatty acids in Atlantic salmon.

Impact of In Vitro Digestion on the Digestibility, Amino Acid Release, and Antioxidant Activity of Amaranth (Amaranthus cruentus L.) and Cañihua (Chenopodium pallidicaule Aellen) Proteins in Caco-2 and HepG2 Cells.

This study evaluated the impact of in vitro gastrointestinal digestion on the digestibility, amino acid release, and antioxidant activity of proteins from amaranth (Amarantus cruentus L.) and cañihua (Chenopodium pallidicaule Aellen). Antioxidant activity was assessed using ORAC, ABTS, DPPH, and cellular antioxidant activity (CAA) assays in human intestinal Caco-2 and hepatic Hep-G2 cell lines. The results showed that amaranth had higher protein digestibility (79.19%) than cañihua (71.22%). In addition, intestinal digestion promoted the release of essential amino acids, such as leucine, lysine, and phenylalanine, in both protein concentrates. Concentrations of amaranth and cañihua proteins, ranging from 0.125 to 1.0 mg mL-1, were non-cytotoxic in both cell lines. At a concentration of 0.750 mg mL-1, simulated gastrointestinal digestion enhanced cellular antioxidant activity. Intestinal digest fractions containing peptides >5 kDa were the principal contributors to CAA in both cell lines. Notably, cañihua proteins exhibited high CAA, reaching values of 85.55% and 82.57% in Caco-2 and HepG2 cells, respectively, compared to amaranth proteins, which reached 84.68% in Caco-2 and 81.06% in HepG2 cells. In conclusion, both amaranth and cañihua proteins, after simulated gastrointestinal digestion, showcased high digestibility and released peptides and amino acids with potent antioxidant properties, underscoring their potential health benefits.

OCENA JAKOŚCI ZIELONKI UZYSKANEJ Z MIESZANEK ŁUBINU WĄSKOLISTNEGO Z PSZENŻYTEM JARYM

The aim of the study was to evaluate the influence of the share of components in the mixture of narrowleaf lupin with spring triticale and the harvest stage on the quality of green fod- der for livestock. Two factors were analysed in a three-year experiment: Share of components in the mixture at sowing narrowleaf lupin + spring triticale (seed·m−2): 120 + 0, 90 + 150, 60 + 300, 30 + 450, 0 + 600, harvesting stage: I – narrowleaf lupin flowering stage, II – narrowleaf lupin flat green pod stage. The most favourable quality of green fodder was obtained from narrowleaf lupine, while among the mixtures from the mixture with the highest share of narrowleaf lupine at seed sow- ing. These crops were characterised by the lowest concentration of crude fibre and its fractions and the highest digestibility, dry matter intake and relative feed value. The harvesting of mixtures at the narrowleaf lupin flowering stage proved to be more favourable in terms of the quality of the green fodder obtained. In order to obtain valuable fodder for livestock, the cultivation of mixtures with a seed share at sowing of 90 + 150 of narrow-leafed lupine and spring triticale, respectively, should be recommended.

Efficient use of multiculturally cultivated pond fish is a vector for the developmentи of the production of high-quality fish products

Attracting new raw material sources is based on the existing experience of using fish from the national internal and external water bodies in food, including seas, oceans, rivers, lakes and artificial reservoirs. The purpose of the research is to substantiate the conditions and create high-quality fish products for wide consumer demand based on paddlefish processed product. The object of the research is fresh and chilled American paddlefish grown in polyculture conditions together with silver carp for 2 years, as well as developed fish products produced in laboratory conditions. A generalization of the available information and the results of the research allow us to identify the paddlefish as a highly valuable raw material resource for the production of high-quality fish products. The paddlefish is a technologically advanced fish; it lacks scales, has small costal and intercostal bones and well-developed muscle tissue, and is able to increase the mass rapidly. Paddlefish meat and liver contain all the essential amino acids and biologically active substances. Therefore, these raw materials have significant potential in satisfying physiological needs of the body, and also have high digestibility at the level of 90 and 92%, respectively. The implementation of the developed optimization program has made it possible to create recipe-component solutions for new fish products: meat and fish cutlets, pate and canned food. In the course of determining the quality, nutritional and biological value, technological, consumer and quality advantages of the developed products, created on the basis of raw material combinations of pond fish cutting products grown in polyculture conditions have been established. Modified technological production schemes have been recommended and tested.

Biotransformation approaches using solid-state fermentation and germination with high-intensity ultrasound to produce added-value hemp protein nanoaggregates

Hemp protein, with superior nutritional content and high digestibility, has attracted significant interest in recent years. However, like other plant protein sources, hemp protein has still suffered from underutilization in industrial applications due to its poor solubility attributes. To overcome this limitation, this study aimed to use biotechnological approaches such as germination (1, 3, 5 days) and solid-state fermentation using Lactobacillusplantarum and Bacillus subtilis to enhance the physicochemical, functional, and bioactive properties of hemp protein. The high-intensity ultrasound combined with these treatments for further modifications. The protein recovery in the defatted flour increased by 42% in germinated isolates compared to the untreated isolate. The primary structure changes were proven by degrading high molecular weight proteins to lower weights in SDS-PAGE. The secondary and tertiary structure changes of isolates were observed in FTIR, CD spectra, DSC, and free SH groups. While the particle sizes of isolates were reduced by 83%, solubility increased by 133% in fermented and ultrasonicated isolates. Water, oil absorption capacities and emulsion activities were increased by 103%, 194%, and 300%, respectively, in modified isolates compared to the untreated isolate. Total phenolic and antioxidant activities of isolates improved in germinated and fermented isolates. Fermentation, germination, and ultrasonication are promising, green, safe, alternative biomodification techniques that may effectively improve protein functionality. These clean-labeled proteins can also be used as bioactive agents in the food industry.

Revealing the synergy mechanisms of organic components anaerobic co-digestion from the prevailing tendency of endogenous inhibitors

The anaerobic co-digestion (AcoD) test among three organic components (model compounds) under high feeding load was carried out in this study, then the dynamic change of intermediate metabolic inhibitors was detected and analyzed to identify the interaction mechanism among organic components from the prevailing tendency of endogenous inhibitors. Carbohydrate and protein show significant two-way synergistic effects for methane production. The addition of protein can supplement additional alkalinity to alleviate the sharp drop of pH (from 4.56 to 6.73) and avoid the acidification caused by high concentration of carbohydrate. Additionally, volatile fatty acids (VFAs) produced by carbohydrate can transform free ammonia to ammonium ion with the largest drop of 54%, thus reducing ammonia toxicity. Carbohydrate and lipid show one-way synergistic effects, namely, lipid can reduce VFAs accumulation by 49% through long chain fatty acids (LCFAs) inhibiting action, and then avoid complete rancidity of carbohydrate fermentation at high concentration. However, protein and lipid show serious two-way antagonistic effects, especially under high load digestion. On one hand, LCFAs would weaken ammonia volatilization and thus aggravate ammonia inhibition; On the other hand, protein would not only accelerate the formation of LCFAs inhibition by promoting lipid hydrolysis, but also transform the degradation pathway of oleic acid (unsaturated LCFAs) and then increase the proportion of stearic acid from 5.17% to 40.33%, which is of higher toxicity than palmitic acid.

Fermentation of rain tree (Samanea saman) seed meal using mixed microbes to improve its nutritional quality

Abstract. Anwar A, Zainuddin, Djawad MI, Aslamyah S. 2023. Fermentation of rain tree (Samanea saman) seed meal using mixed microbes to improve its nutritional quality. Biodiversitas 24: 5863-5872. Rain tree (Samanea saman) seed meal is a source of protein; however, its utilization remains limited due to the presence of anti-nutrients, such as tannins acting as protein inhibitors, high crude fiber content, dissolved protein, and low digestibility of dry and organic matter. Fermentation using mixed microbes potentially enhances the nutritional value of rain tree seed meal. This study aims to improve the nutritional quality and reduce anti-nutritional factors in rain tree seed flour using mixed microbes at various doses and incubation times in vitro. Microbes utilized in this study include Bacillus sp., Saccharomyces cerevisiae, and Rhizopus sp. The study was designed using a Factorial Completely Randomized Design, using two factors, i.e., 3 doses of mixed microbes (0, 1.5, 3, and 4.5 mL/100 g rain tree seed meal) and 3 different incubation times (42, 72 and 96 hours). There were significant interactions between the microbe doses and incubation times. The treatment of 4.5 mL of mixed microbes/100 g rain tree seed meal and a 72 hours incubation time reduced substantially crude fiber content (59.60%) and crude fat (73.20%), coupled with an increase in crude protein content (11.62%), NFE (6.52%), dry matter digestibility (DMD) (36.78%), organic matter digestibility (OMD) (50.42%), and dissolved protein content (20.27%). Tannin content reduced significantly (37.72%) at the treatment of 4.5 mL of mixed microbes/100g rain tree seed meal with an incubation time of 96 hours. These findings suggest that rain tree seed meal, subjected to fermentation for 72 hours or more, improves nutritional quality, DMD, and OMD.

Assessment of energy and biological value of Cherax quadricarinatus meat after feeding crayfish with different types of feed

Cultivation of the Australian red-clawed crayfish Cherax quadricarinatus has become popular in many countries due to the rapid growth rate, high nutritional and biological value of the meat, and quite significant demand among consumers. The aim of our study was to determine the chemical, amino acid and fatty acid composition of Cherax quadricarinatus crayfish meat and its energy value when fed with different types of feed. The fatty acid composition of crayfish meat was determined by the chromatographic method, and the amino acid composition by the capillary electrophoresis method. It was established that when feeding crayfish with the developed Decapodafood feed, the energy value of crayfish meat was 4.3 kcal more than when feeding crayfish with aquarium feed Ancistrus menu. Feeding with Decapodafood promotes a higher content of essential amino acids compared to feeding with commercial aquarium food Ancistrus menu. In particular, a higher content of essential amino acids such as threonine, valine, methionine, lysine in the meat was statistically probable. In addition, a high biological value and digestibility of crayfish meat was found, as the sum of ΣEAA/ΣNEAA in all samples was more than 80%, which is on average 20% more than the standard indicator recommended by FAO/WHO. Feeding crayfish with Decapodafood helps to reduce saturated fatty acids in meat and increase unsaturated ones. In particular, a 1.9 times lower content of lauric acid and 1.5 times lower margaric acid was found in the meat of crayfish fed Decapodafood, compared to crayfish fed Ancistrus menu aquarium food, and myristic and pentadecanoic acid were on average 1.3 times smaller. Among unsaturated fatty acids, a probable increase of 1.4 times was noted for palmitoleic and docosahexaenoic acids, compared to their content in control meat. The content of other polyunsaturated fatty acids (linoleic and eicosapentaenoic), although higher, was insignificant. Therefore, feeding Cherax quadricarinatus crayfish with Decapodafood helps to improve the energy and biological value of the obtained meat, which makes it a highly digestible and delicate product. Key words: Cherax quadricarinatus, crayfish meat, Decapodafood, amino acid, fatty acid composition of meat.

A model-based approach for evaluating the effects of sludge rheology on methane production during high solid anaerobic digestion: Focusing on mass transfer resistance

Mass transfer process is vital for biochemical reactions, which is related to sludge rheology. But this inherent interaction has not yet been established for sewage sludge anaerobic digestion (AD). This work investigated the role of sludge rheology in bio-kinetics of AD. AD of sodium acetate and microcrystalline cellulose under different total solids (TS of 6.29%, 7.63%, 9.02%, 11.06%) of digested sludge was set up to identify the role of sludge rheology. Results showed that rheological properties, e.g., viscosity and viscoelasticity, increased with the increase of TS content. These resulted in negative effect on methane production of sodium acetate with lag phase increased from 0.93 d to 1.57 d, but almost no effect was observed for microcrystalline cellulose. An extended ADM1 model was developed, which revealed that enhanced sludge rheological properties increased mass diffusion resistance and reduced uptake rate of acetate. This effect can be described explicitly by mass transfer coefficient (kla_Sac). However, from the original ADM1, this effect was indistinctly lumped in apparent half-saturation coefficient (ksac). Based on the role of sludge rheology in mass transfer and bio-kinetics, it is suggested that modeling the methane production based on TS contents and sludge rheology is possible, which should be considered in giving an insight into the micro-scale phenomena (e.g. mass transport, bio-kinetics) in high solid AD.

Humifloc™: An improved solid waste responsible for sustainable aquaculture

The present experiment intended to find out the alternative usages of solid wastes, left aside due to their non-usage for the benefit of animals. Among the different types of solid wastes, organic bio-degradable solid wastes from the municipal area comprising non-hazardous properties had been considered for enhancing aquaculture productivity. Organic solid wastes along with the vermicast, produced by certain epigeic earthworms (Eisenia fetida, Eudrilus eugeniae,Perionyx excavatus) from the mixture of raw cow dung (added externally), certain beneficial herbs (Neem: Azadirachta indica, Indian-Almond: Terminalia catappa, Kule Khara: Hygrophila auriculata, and Ashwagandha: Withania somnifera), turmeric (Curcuma longa), and whole banana tree (Musa paradisiaca) were the basic ingredients to represent the ‘improved solid wastes’(Trade named: Humifloc™), produced through a series of natural procedures finally to act as a supplement. Periodical [start-up dose: 10 kg acre−1 (single time); maintenance dose: 05 kg acre−1 fortnightly up to 90 days] direct administration of Humifloc™ was done into the experimental ponds reared with teleostean fishes [Catla (Catla catla), Rahu (Labeo rohita), Magur (Clarias batrachus), and Koi (Anabas testudineus) 2:5:1:1] up to 90 days in the dry season (November to January) and were fed with farm-prepared farm-made-aqua-feed or ‘farm-feed’. Three ponds [(one control (C farm-feed only): and two treatments (T: P1 & P2 farm-feed plus Humifloc™)] were considered while observing the growth performances and alteration in tissue biochemistry of the experimental fish species. A comprehensive study based on growth and biochemical parameters of various tissues indicated a quadratic response. Under Humifloc™ exposure, pond water depicted an equilibrium in water parameters like in pH, ammonia, and nitrate, while the fishes depicted faster metabolic rate, higher digestibility, balancing of glucose homeostasis, and higher brain signalling which might finally result in elevation of growth performances with higher productivity, directly affecting to the profitability of the poor fish farmers.

186 Amino Acid Digestibility of Various Protein-Based Ingredients Using the Precision-Fed Cecectomized Rooster Assay

Abstract Given their high protein quality and sustainable production practices, there is growing interest in using single cell-based proteins in pet foods. Because there has been a lack of testing on these proteins, the objective of this experiment was to determine the amino acid (AA) digestibilities of a single cell protein and other protein-based ingredients using the precision-fed cecectomized rooster assay. Test ingredients included: Calysta microbial protein (MP), chicken meal (CM), corn gluten meal (CGM), pea protein (PP), and black soldier fly larvae (BSFL). All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. Thirty cecectomized roosters (n = 6/ingredient) were randomly assigned to test ingredients. After 24 h of feed withdrawal, roosters were tube-fed 15 g of test ingredient and 15 g of corn. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using 5 additional cecectomized roosters. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to AAFCO nutrient profiles, FEDIAF nutritional guidelines, and NRC recommended allowances for adult dogs, adult cats, growing puppies, and growing kittens. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P &amp;lt; 0.05 being significant. All of the reactive lysine:total lysine ratios, an indicator of heat damage, were greater than 0.9 except for CM (0.86). All indispensable AA had digestibilities &amp;gt;85% for MP, with indispensable AA digestibilities being &amp;gt;80% for all ingredients. In general, CGM had the greatest AA digestibilities, while CM had the least AA digestibilities. Two exceptions were the digestibilities of lysine and tryptophan, which were greatest in MP. Lysine digestibility for MP (92.3%) was greater (P &amp;lt; 0.01) than that of all other ingredients. Tryptophan digestibility for MP (97.2%) was greater (P &amp;lt; 0.0001) than that of CM, CGM, and PP. Threonine and valine digestibilities were also greater for MP. Threonine digestibility was greatest for CGM (91.0%) and MP (88.6%), being greater (P &amp;lt; 0.0001) than that of the other ingredients. Valine digestibility was greatest for CGM (93.3%), PP (89.3%), and MP (89.3%), being greater (P &amp;lt; 0.001) than that of CM. DIAAS-like calculations estimated the protein quality of each ingredient, with the limiting AA of each depending on the reference used (NRC; AAFCO; FEDIAF) and life stage (growing; adult) and species (dog; cat) of animal in question. For dogs, limiting AA were most commonly methionine, threonine, and tryptophan. For cats, limiting AA were most commonly lysine and methionine. Further research in dogs and cats is necessary to confirm sufficient palatability and digestibility. However, our data suggest that the MP tested is a high-quality protein source with high AA digestibilities, and may serve as a valuable protein alternative for pet foods.

Tithonia diversifolia Improves In Vitro Rumen Microbial Synthesis of Sheep Diets without Changes in Total Gas and Methane Production

Among the alternatives identified as capable of making livestock farming a more efficient activity and reducing its environmental impact, the use of feeds with high digestibility and the use of non-conventional fodder species can be highlighted. Tithonia diversifolia (Hemsl.) A. Gray (TD) has already gained attention as a feed for ruminants. Nonetheless, there has been little discussion about the impacts of this plant on the rumen dynamics that lead to better animal performance. The aim of this study was to assess how increasing levels of TD could affect ruminal microbial biomass synthesis, degradability, and in vitro gas production (IVGP) of diets. Four diets were evaluated: a control diet (TD0: 400 g kg−1 soybean meal and maize grain, and 600 g kg−1 Tifton 85 hay (Cynodon spp.)) and three increasing levels of TD (TD9: 90, TD27: 270, and TD45: 450 g kg−1–dry matter basis) as a replacement for dietary roughage. A 96 h IVGP assay was carried out and five incubation times (2, 4, 10, 24, and 96 h) were used for degradability determination. Gas produced, methane (CH4), degradability of organic matter (IVDOM), short-chained fatty acid (SCFA) production, partitioning factor (PF), and microbial biomass (MB) were evaluated among treatments. There was no significant effect (p &gt; 0.05) between TD inclusion and IVGP at most incubation times; only at 6 h of incubation did gas production increase linearly with TD inclusion (R2 = 0.19; p &lt; 0.05). TD inclusion had no effects on CH4. IVDOM increased linearly with TD inclusion at 6 and 10 h, with TD45 being more degradable than the control diet at 6 h only. There was a positive linear relationship (R2 = 0.20; p &lt; 0.05) between TD inclusion and PF. TD45 had significantly higher PF values than the control. MB also increased linearly (R2 = 0.30; p &lt; 0.05) with TD inclusion, and all diets with TD had significantly more MB than the control diet. The inclusion of TD at the levels used in this work was revealed to have a positive impact on microbial protein synthesis, which could be related to the higher microbial efficiency of increased substrate quality.

Heat-induced gelation of SAM myofibrillar proteins as affected by ionic strength, heating time and temperature: With emphasis on protein denaturation and conformational changes

There is a growing consumption of scallop adductor muscle (SAM) based food due to its great nutritional value and high digestibility. SAM gelation has a key effect on final products, however, the gelling properties of SAM, particularly the denaturation and conformational changes of proteins, are far less known. Thus, the present study aimed to improve our understanding on the gelation of SAM as affected by different heating temperatures, time, and ionic strength at low salt concentration ranges. Protein denaturation is the primary reason for the physicochemical changes of minced SAM during thermal gelling. Both gel strength and storage modulus showed positive correlations with heating temperature and time. However, the water holding capacity decreased gradually from 60 to 90 °C due to the shrinkage of myofibril proteins induced by protein denaturation, resulting in the transformation of immobilized water into free water, as proved by LF-NMR results. DSC and FTIR results indicated that heating at 90 °C led to complete degeneration of myosin and actin, and partial conversion of α-helices to β-sheets and random coil, resulting in a more rigid gel. It was further discovered that rapid heating (90 °C-10min) of low salt SAM at 1.5% NaCl concentration during gelation contributed to a superior gel strength and the reinforcement of fine-stranded three-dimension gel matrix as revealed by SEM. The investigation of heat-induced SAM provides a practical value for the processing of low-salt minced SAM products for the food industry.

Composite nanofiber membranes to enhance the performance of high solids anaerobic digestion of organic rural household waste resources

This study investigated the effect of using nanofiber membrane composites containing Prussian blue-like compound nanoparticles (PNPs) with a stainless steel mesh as the carrier (NMCs) to relieve ammonia nitrogen inhibition of rural organic household waste during high-solid (total solid content of 15 %) anaerobic digestion (AD) and increase methane production. NMCs with different PNP contents were added to high-solid AD. When NMC with 15 % PNPs was added, the concentrations of volatile fatty acids and ammonia nitrogen were lower than those of the blank control group, and the methane yield was the highest (301.31 mL/g volatile solids [VS]), at 2.8 times higher than that of the blank control group. The R2 value of the modified Gompertz equation was 0.997. During digestion, the activities of extracellular protease and coenzyme F420 were higher than those of the control group. NMCs were successfully recovered at the end of the experiment, and confocal scanning three-dimensional electron micrographs indicated that NMC with 15 % PNPs of NMCs had stronger biological activity; microbial community structure analysis indicated increased abundance of hydrogenotrophic methanogens in this group. The study provides a new solution for improving the efficiency of biogas production and the recycling of exogenously added materials.

Nutritive value and in-vitro digestibility of peels and pomaces of different citrus species

The nutritive value and invitro digestibility of agro-industrial byproducts of Citrus aurantium, Citrus paradisi, Citrus reticulata, Citrus limon and Citrus sinensis were assessed for their feed modification potential. Nutritive value assessment was done through chemical analysis while the ANKOM Daisy II incubator method was used to determine the invitro digestibility. At p&gt;0.05, there was no statistical significance for nutritive value of the citrus byproducts for the five species. The agro-industrial by-products had significantly different phenolic content. Invitro digestibility of the peels significantly differed from the pomaces (p&lt;0.001). The byproducts of the five citrus species showed potential to be considered as non-forage energy sources in ruminant feed. Lemon byproducts had high protein but not sufficient as a single protein source while bitter orange pomace may be considered for antioxidant capacity and high digestibility. Abundance of citrus agro-industrial byproducts, nutritive value potentials and their digestibility makes it a good strategy for ruminant feed modification and utilization.

Low-temperature pretreatment by AlCl3-catalyzed 1,4-butanediol solution for producing ‘ideal’ lignin with super-high content of β-O-4 linkages

High contents of internal β-O-4 linkages in lignin are critical for high-yield production of high-value aromatic monomers by depolymerization. However, it remains great challenge due to lack of suitable protection strategy. In this work, a very effective lignin-first strategy was developed to produce ideal lignin with a super high content of β-O-4 linkages (up to 72 %) from poplar, in which the pretreatment was undertaken at low temperatures of 90–130 °C with the use of AlCl3-catalyzed 1, 4-butanediol solution. 2D-HSQC NMR spectra revealed that lignin β-O-4 linkages were protected from etherification of the OH group by 1, 4-butanediol at the α position of lignin aliphatic chains. Besides, the OH groups at the γ position of lignin was also etherified, leading the formation of a structure of Ph-CH=CHCH2O(CH2)4OH. Interestingly, structure protection facilitated the formation of lignin nanoparticles via self-assembly (<100 nm). In addition, it was observed from pyrolysis results that addition of 1, 4-butanediol remarkably protected the structure of lignin by avoiding condensation, promoting the production of aromatics. The cellulose-rich fraction possessed a high cellulose digestibility of 91.64 % by enzymatic hydrolysis at a cellulase dosage of 15 FPU/g cellulose, approximately 6-fold untreated poplar (15.91 %). This low-temperature lignin-first strategy was of great importance for multi-products biorefining lignocellulose because it leads to the production of both lignin with super high content of β-O-4 linkages for depolymerization and highly digestible cellulose for sugar production.

Potential of hydrolyzed wheat protein in soy-based meat analogues: Rheological, textural and functional properties

Hydrolyzed proteins, which are considered to possess significant bioactive properties such as antioxidant and high digestibility, have garnered increasing interest as food ingredients. This study investigates the feasibility of using hydrolyzed wheat gluten (HWG) and soy protein concentrate (SPC) in various ratios to create meat analogues using high-moisture extrusion technology. Results indicate that meat analogues with 40% HWG addition to SPC have a better texture and greater similarities in terms of hardness, chewiness, and toughness to chicken meat than meat analogues with 40% wheat gluten (WG) addition to SPC. Additionally, the meat analogues with HWG showed high antioxidant capacity, protein digestibility, and amino acid composition, indicating potential health benefits. These findings indicate that HWG could serve as a texture modifier to improve both the texture and nutritional content of meat analogues.