Digestion Of Fraction Research Articles

Stale bread waste recycling as ingredient for fresh oven-baked white bread: effects on dough viscoelasticity, bread molecular organization, texture, and starch digestibility.

Wasted food produced for human consumption is estimated at 33% globally, and bread is the food product with the highest percentage. There is an ongoing drive to reincorporate food waste still useful and safe into the production chain of food for human consumption. This work aims to contribute to the study of the feasibility of recycling stale bread waste flour (BWF) into fresh oven-baked white bread, by replacing 0, 20, 40, 60, 80, and 100 g/100 g of the wheat flour with BWF. Storage and loss moduli increased as the BWF content increased. The baked loaf exhibited decreased lightness and yellowness but increased redness. Increasing BWF contents produced decreased loaf volume and hardness but increased moisture content. Fourier-transform infrared analysis showed that the BWF addition induced important changes in the water, protein, and starch molecular organization. Therefore, starch digestibility showed reductions in both rapidly and slowly digestible starch fractions. Principal component analysis revealed that replacements of up 20 g/100 g can produce white bread with textural, colour, and starch digestibility characteristics like that of the control bread. The fresh oven-baked white bread variation produced by replacing 20 g/100 g of the wheat flour with BWF exhibited comparable colour, volume, texture, and starch digestibility features as a control bread did made with 0 g/100 BWF. Higher replacement percentages of wheat flour by stale BWF produced unsuitable drawbacks in the white bread characteristics, but those might be deemed as convenient in other types of bakery products. © 2023 Society of Chemical Industry.

Structural basis for rice starch multi-digestible fractions revealed by consecutive reaction kinetics model.

Starch-based foods (e.g. rice) usually contain multiple starch fractions with distinct digestion rate constants, although their nature is currently unknown. The present study applied the recently developed consecutive reaction kinetics model to fit the in vitro digestion curves for starch fractions deconvoluted from the overall digestograms to differentiate their binding and catalysis rates to starch digestive enzymes. The fitting parameters were then correlated with starch molecular structures obtained from published data to understand starch structural features determining the binding and catalytic rate constants. Binding and catalysis rates for the rapidly (RDF) and slowly digestible starch fraction (SDF) were controlled by distinct starch structural features. Typically, (i) the binding rate constant for RDF was negatively correlated with the amount of amylose short to intermediate chains, whereas it was positively correlated with the relative length of amylopectin intermediate chains; (ii) the catalysis rate constant for RDF was negatively correlated with the amount of amylose short to intermediate chains, relative length of amylose intermediate chains and amount of amylopectin long chains, whereas it was positively correlated with starch molecular size as well as relative length of amylopectin intermediate chains; (iii) and the catalysis rate constant for SDF was negatively correlated with the amount of amylopectin long chains, whereas it was positively correlated with starch molecular size. These results provide a better understanding of the nature of different starch digestible fractions and the development of foods such as rice with slow starch digestibility. © 2023 Society of Chemical Industry.

Evaluation of postprandial glycemic response in rats (Wistar) fed with different starch sources.

The consumption of readily digestible starch sources, such as corn, can negatively impact endocrine disorders related to hyperglycaemia in predisposing animals. In this sense, starch sources containing slowly digestible and resistant fractions can assist glycemic control. The present study analyzed the postprandial glycemic response and blood variables of rats fed with four extruded diets containing corn, brown rice, sweet potatoand pea as the main starch source. Thirty-two male Wistar rats (90 days old) were divided into groups of eight animals each. The rats received one of the experimental diets for 30 days according to a completely randomised design. The glycemia was measured on the 29th and 30thdays. The glycemia measured on the 29th day was analyzed at 0, 30, 60, 120and 240 minafter oral administration of 50% glucose solution. On the 30th day, the same protocol was repeated after providing 3 g of the experimental diet for each animal to obtain the glycemic curve. After the euthanasia on the 30th day, 7 ml of blood was collected via cardiac puncture for glycated haemoglobin (HBA1c), triglycerides, cholesterol, and aspartate and alanine aminotransferases analysis. Diets with peaand sweet potatoprovided lower glycemic index, average and maximum glycemia, and glycemic increment in relation to the other starch sources (p < 0.05). Animals fed with the corn diet had higher serum concentrations of triglycerides and HBA1c than the other treatments (p < 0.05). Results demonstrated that peaand sweet potatoare interesting starch sources for the control of metabolic disorders related to glycemia.

Impact of Mangrove Leaves (Rhizophora apiculata) in Limewater on Nutrients Digestibility, Rumen Ecosystem and in vitro Methane Production

The Mangrove is one of the plants that live in coastal areas, because a lot of their availability, mangrove leaves can be used as animal feed. The problem with this mangrove is contained a fairly high tannin which can be harmful to livestock. This study aims to determine the impact of boiled mangrove leaves (Rhizophora apiculata) with lime water on tannins, digestibility, rumen characteristics, and in vitro methane production. The design used in this study was a randomized block design using 4 treatments and 5 replications. The treatments were boiled with the respective concentrations of quicklime water as follows, P1 (without boiling), P2 (5% lime water), P3 (10% lime water), and P4 (15% lime water) for 10 min. The results showed that boiling mangrove leaves with 5% lime water showed highly significant (p<0.01) results on total tannins content, nutrient digestibility, rumen fluid characteristics, and reduced methane gas content. Nutrient digestibility includes among others: Dry matter digestibility (65.18%), organic matter digestibility (66.31%), crude protein digestibility (67.90%), and increased digestibility of fiber fractions including NDF digestibility (59.01%), ADF digestibility (55.75%), cellulose digestibility (64.02%), hemicellulose digestibility (69.61%) and increased rumen fluid characteristics such as NH3 contents (4.32 Mg/100 mL) and VFA content (130.2 mm) and Methane gas (231.39 mL/gDM). The results of this study concluded that boiling mangrove leaves in lime water at a concentration of 5% for 10 min contributed to the most prominent total tannins (4.54%) and digestibility of nutrients.

Parallel generation of extra advanced glycation end-products during co-digestion of whey proteins and α-dicarbonyls in a simulated gastrointestinal model.

Advanced glycation end-products (AGEs) are a group of heterogeneous compounds formed during the Maillard Reaction (MR) and have been proven to be detrimental to human health. In addition to thermally processed foods, the digestive tract may be an additional site for exogenous AGE formation since the MR would possibly occur between (oligo-)peptides, free amino acids, and reactive MR products (MRPs) such as α-dicarbonyl compounds (α-DCs) along the digestion. In this study, through establishing a simulated gastrointestinal (GI) model consisting of whey protein isolate (WPI) and two typical α-DCs, i.e., methylglyoxal (MGO) or glyoxal (GO), we first validated that co-digestion of WPI with α-DCs generated extra amounts of AGEs in a precursor-dependent manner, especially seen in the intestinal stage. At the end of GI digestion, the contents of total AGEs in WPI-MGO and WPI-GO systems were 4.3-242 and 2.5-73.6 times higher than those formed in the control system, respectively. Evaluation of the protein digestibility further showed that AGE formation along the digestion process slightly affected the digestibility of whey protein fractions. However, as sequenced and identified by high-resolution mass spectrometry, different types of AGE modifications were identified in peptides released from β-lactoglobulin and α-lactalbumin in the final digests, as well as changes in peptide sequence motifs. This suggested that the glycated structures formed during co-digestion affected the action of digestive proteases toward whey proteins. Overall, these results highlight the GI tract as an additional source of exogenous AGEs and provide new insights into the biochemical consequences of MRPs in heat-processed foods.

Treatment of Liquid Fraction of Digestate by Integrated Process Struvite Precipitation—Forward Osmosis

The research undertaken in this paper was aimed at determining the effect of struvite precipitation, one of the potential products that can be obtained during digestate management, on the performance of the non-pressurized membrane process—forward osmosis (FO). The effect of using an integrated struvite precipitation—forward osmosis process to treat the digestate liquid on the changes in the properties of organic substances present in the treated solution (particle size distribution, ζ-potential) was analysed as well. The study was conducted for the liquid fraction of municipal waste biogas plant digestate. The obtained results demonstrate the suitability of this process for recovering water from liquid digestate. It was found that forward osmosis conducted for a digestate pre-treated by chemical struvite precipitation leads to higher water flux values and increased salt concentration in the receiving solution (from 0.5 to 3 mol/dm3 NaCl). There is practically no concomitant infiltration of organic substances into the receiving solution. Therefore, the use of 3 mol/dm3 NaCl as a draw solution results in the recovery of the highest volume of water per unit of time. An analysis of the particle size distribution shows that the removal of the macromolecular fraction of organic compounds from the digestate mainly takes place simultaneously with the chemical precipitation of struvite. It was found that an increase in the concentration of the draw solution, which allows for greater water recovery, resulted in the aggregation of the concentrated organic molecules.

The Effects of Starch Molecular Fine Structure on Thermal and Digestion Properties of Rice Starch.

Whole white rice is a major staple food for human consumption, with its starch digestion rate and location in the gastrointestinal tract having a critical role for human health. Starch has a multi-scale structure, which undergoes order-disorder transitions during rice cooking, and this structure is a major determinant of its digestibility. The length distributions of amylose and amylopectin chains are important determinants of rice starch gelatinization properties. Starch chain-length and molecular-size distributions are important determinants of nucleation and crystal growth rates, as well as of intra- and intermolecular interactions during retrogradation. A number of first-order kinetics models have been developed to fit starch digestograms, producing new information on the structural basis for starch digestive characteristics of cooked whole rice. Different starch digestible fractions with distinct digestion patterns have been found for the digestion of rice starch in fully gelatinized and retrograded states, the digestion kinetics of which are largely determined by starch fine molecular structures. Current insights and future directions to better understand digestibility of starch in whole cooked rice are summarized, pointing to ways of developing whole rice into a healthier food by way of having slower starch digestibility.

Changes in the Composition of Digestate Liquid Fraction after Ozone and Ultrasonic Post-Treatment

There is a growing concern about environmental pollution with digestate, which is produced in significant amounts in the anaerobic digestion process. The inappropriate application of digestate in agriculture may lead to ammonia emission to the atmosphere, nutrients infiltration to groundwater and surface waters eutrophication. There is a great interest in the development of efficient downstream technologies that will help better handle digestate. This study assessed the effect of three different disintegration methods (ozonation, ultrasonication, combination of ozonation and ultrasound) on solids content, nutrient concentration and biodegradability of the liquid fraction of sugar beet pulp digestate. The influence of initial pH (7, 8, 9), ozone dose (0.05–0.45 g O3/g TS), specific ultrasound energy (10,381–51,903 kJ/kg TS) and vibration amplitude (50, 100%) on the performance of digestate liquid fraction treatment was investigated. The highest removal efficiencies of organic substances, total and ammonia nitrogen averaging at 13.81, 20.04 and 28.70%, respectively, in separate ozonation and ultrasonication processes, was obtained at ozone dose of 0.25 g O3/g TS, specific energy of 41,522 kJ/kg TS and amplitude of 100%. The application of combined processes, first ultrasonication and then ozonation, resulted in an increase in the above-mentioned removal efficiencies to 58.16, 36.60 and 48.71%, respectively.

Definition of starch components in foods by first-order kinetics to better understand their physical basis

Starch-based foods frequently contain different starch digestible fractions, with distinct digestion rates and locations in human upper gastrointestinal tract. Understanding the physical basis for these starch components is critical for developing foods with low glycemic index (GI) values. Conducting first-order kinetics analysis has been able to extract information on starch digestion properties, with solid physical basis. However, there is currently no clear procedure in terms of defining different starch fractions by first-order kinetics analysis. This review proposes that starch-based foods can be categorized as structurally homogenous or heterogenous starch systems by fitting their starch digestograms to the first-order kinetics model, which are characterized by a single set or multiple sets of digestion rate constants and the fractions remaining undigested at long times during in vitro digestion. In line with starch hierarchical structures, it helps understand the structural origins for different starch components in foods, which can ultimately help the development of functional foods with low GI. Procedure to identify the starch fractions in starch-based foods to better understand their physical basis. SF is single fraction. RDF represents rapidly digestible starch fraction, while SDF represents slowly digestible starch fraction. • Starch-based foods often contain multiple starch fractions. • These foods can be defined as structurally homogeneous or heterogenous foods. • This definition helps the understanding of physical basis for starch digestibility.

Balance of total mass and nitrogen fluxes through consecutive digestate processing steps: Two application cases

The high water content and low nutrient concentration of digestate complicate its storage, transportation, and utilization. Subsequent digestate processing can effectively remove water and influence nutrient partitioning among digestate fractions and final products.The current study was carried out to evaluate the performance of two typical digestate processing chains, solid and liquid ones, respectively, and to give practical recommendations for optimization. Two fully operating biogas plants with advanced heat utilization were considered as data sources. The digestate mass flow balance of dry matter (DM), water, total N (TN), and ammonium-N mass flows was performed and the efficiency of the examined processing units was calculated.It was found that solid-liquid separation of raw digestate shifted 73–87% of TN and 60–93% of NH4–N to the liquid phase. Subsequent drying of separated solid fraction removed about 6% of the initial water and required 84% less thermal energy per kg N recovered than the processing of separated liquid. The final product, pellets, contained 14% of initial TN, but only 2% of initial NH4–N as a result of microbial conversion of inorganic N during drying.Vacuum evaporation of separated liquid fraction removed 34% of the initial water and left a DM-rich concentrate. At the same time, an ammonium sulfate solution (ASS) containing 21% of initial TN and 34% of initial NH4–N was produced.Both evaluated processing chains showed specific advantages and challenges. Solid products were characterized by a high share of recalcitrant organic compounds and could serve as a soil improver. Liquid processing concentrated plant-available N in ASS, which could be used as valuable inorganic fertilizer.

Matured Manure and Compost from the Organic Fraction of Solid Waste Digestate Application in Intensive Apple Orchards

In intensive fruit growing systems, the recovery and maintenance of soil fertility play a crucial role in both environmental protection and sustainable support to plant productivity. The circular economy approach adopted at the EU level strongly promotes the use of organic products instead of mineral fertilizers. This work focuses on two different soil improvers, compost from the organic fraction of municipal solid waste digestate (CO) and "matured" manure, produced after a fast and controlled aerobic treatment in an aerated pile (MM), which were applied in three apple orchards with different soil tillage. The soil improvers have been characterized for amendment and fertilizing properties. After the amendment, the soils were sampled twice a year (Spring and Autumn) for three years. Each sample has been characterized for texture, pH, cation exchange capacity, nutrients, soil organic matter, and micronutrients. The amendments obtained differed on C, N, P, and K contents, but had similar biological stability. The main effects on soils were the increasing of N and soil organic matter after compost application, while the use of matured manure mainly act on available P and exchangeable K. The treatments showed significant effects among fields with a linear increasing trend only for compost. Matured manure showed more effects in earlier times. The data collected aim to improve the knowledge about sustainable management of soil organic matter and organic nutrients in intensive fruit-growing agriculture by using local products.

Biogas digestate as a sustainable phytosterol source for biotechnological cascade valorization.

Every year, several million tonnes of anaerobic digestate are produced worldwide as a by-product of the biogas industry, most of which is applied as agricultural fertilizer. However, in the context of a circular bioeconomy, more sustainable uses of residual digestate biomass would be desirable. This study investigates the fate of the sterol lipids β-sitosterol and cholesterol from the feedstocks to the final digestates of three agricultural and one biowaste biogas plants to assess if sterols are degraded during anaerobic digestion or if they remain in the digestate, which could provide a novel opportunity for digestate cascade valorization. Gas chromatographic analyses showed that feedstock sterols were not degraded during anaerobic digestion, resulting in their accumulation in the digestates to up to 0.15% of the dry weight. The highest concentrations of around 1440 mg β-sitosterol and 185 mg cholesterol per kg dry weight were found in liquid digestate fractions, suggesting partial sterol solubilization. Methanogenic batch cultures spiked with β-sitosterol, cholesterol, testosterone and β-oestradiol confirmed that steroids persist during anaerobic digestion. Mycobacterium neoaurum was able to transform digestate sterols quantitatively into androstadienedione, a platform chemical for steroid hormones, without prior sterol extraction or purification. These results suggest that digestate from agricultural and municipal biowaste is an untapped resource for natural sterols for biotechnological applications, providing a new strategy for digestate cascade valorization beyond land application.

Anaerobic Digestion and Microfiltration of the Liquid Fraction of Pig Slurry: N Mineralization, C-CO2 Emissions and Agricultural Value of the Products

Pig slurry contains valuable nutrients and organic matter, although its high water content makes its management and use as a fertilizer more expensive. It is also an interesting bioenergy resource for biogas production. We propose a treatment that consists of solid–liquid separation followed by the anaerobic digestion of liquid fraction of slurry (LFS) while a microfiltration membrane module concentrates the solids in the digester and removes a liquid fraction of the digestate (LFD). The aims of the work were to evaluate the fertilizer value of the LFS, digestate and concentrated digestate and the possibility of reusing the LFD in agriculture. The LFS contained 72% less dry matter than the slurry. The solid–liquid separation mainly removed N and P. Thanks to microfiltration, the remaining solids were partially recirculated to the digester, concentrating there. To do this, the membrane module continuously removed the LFD, which was made up of 99% water with dissolved elements, mainly C, N, K and Na. The concentrated digestate contained less K, similar amounts of N and P, and more dry matter and C than the initial LFS. The entire slurry treatment affected the mineralization dynamics by increasing recalcitrant C and decreasing labile C without modifying N release. The proposed process allowed taking advantage of the nutrients and stabilized organic matter contained in the LFS, producing a concentrated digestate. LFD did not meet the reclaimed water requirements. However, it could be useful as a fertirrigation solution and a post treatment could be enough to comply with the regulations.Graphical

Benefits of biobased fertilizers as substitutes for synthetic nitrogen fertilizers: Field assessment combining minirhizotron and UAV-based spectrum sensing technologies

Recovery of biobased fertilizers derived from manure to replace synthetic fertilizers is considered a key strategy to close the nutrients loop for a more sustainable agricultural system. This study evaluated the nitrogen (N) fertilizer value of five biobased fertilizers [i.e., raw pig manure (PM), digestate (DIG), the liquid fraction of digestate (LFD), evaporator concentrate (EVA) and ammonia water (AW)] recovered from an integrated anaerobic digestion–centrifugation–evaporation process. The shoot and root growth of maize (Zea mays L.) under biobased fertilization was compared with the application of synthetic mineral N fertilizer, i.e., calcium ammonium nitrate (CAN). The non-invasive technologies, i.e., minirhizotron and unmanned aerial vehicle (UAV) based spectrum sensing, were integrated with the classic plant and soil sampling to enhance the in-season monitoring of the crop and soil status. Results showed no significant difference in the canopy status, biomass yield or crop N uptake under biobased fertilization as compared to CAN, except a lower crop N uptake in DIG treatment. The total root length detected by minirhizotron revealed a higher early-stage N availability at the rooting zone under biobased fertilization as compared to CAN, probably due to the liquid form of N supplied by biobased fertilizers showing higher mobility in soil under dry conditions than the solid form of CAN. Given a high soil N supply (averagely 70–232 kg ha−1) in the latter growing season of this study, the higher N availability in the early growing season seemed to promote a luxury N uptake in maize plants, resulting in significantly (p &amp;lt; 0.05) higher N concentrations in the harvested biomass of PM, LFD and AW than that in the no-N fertilized control. Therefore, the biobased fertilizers, i.e., PM, LFD, EVA and AW have a high potential as substitutes for synthetic mineral N fertilizers, with additional value in providing easier accessible N for crops during dry seasons, especially under global warming which is supposed to cause more frequent drought all over the world.

Changes in Starch In Vitro Digestibility and Properties of Cassava Flour Due to Pulsed Electric Field Processing.

The research aimed to investigate the effect of pulsed electric field (PEF) treatment on cassava flour at mild intensities (1, 2, and 4 kV/cm) combined with elevated levels of specific energy input (250-500 kJ/kg). Influences on starch digestibility, morphological characteristics, birefringence, short-range order and thermal properties were evaluated. Application of PEF at energy input no greater than 250 kJ/kg had negligible influence on the different starch digestion fractions of cassava flour but raised the rapidly digestible starch fraction at a combined electric field strength &gt;1 kV/cm and energy input &gt;350 kJ/kg. Morphological evaluation revealed that at this PEF combination, cassava starch's external structure was consistently altered with swelling and disintegration, albeit some granules remained intact. Consequently, this led to disruption in the internal crystalline structure, supported by progressive loss of birefringence and significantly lower absorbance ratio at 1047/1022 cm-1. These physical and microstructural changes of the inherent starch promoted the shift in gelatinization temperatures to a higher temperature and reduced the gelatinization enthalpy. The study demonstrated that PEF can be utilized to change the starch fraction of cassava flour, which is driven by electric field strength and specific energy input, causing changes in the starch-related properties leading to increased digestibility.

Phosphorus recovery from high solid content liquid fraction of digestate using seawater bittern as the magnesium source

Phosphorus recovery from digestate is considered a challenge because the possible discharge can lead to eutrophication. This study focuses on phosphorus recovery as struvite from the liquid fraction of swine manure digestate at a high total solids concentration, by using a lab-scale crystallizer operated in continuous mode (7 L·d−1). A by-product of salt production (seawater bittern, SWB) was assessed as Mg source for the formation of struvite instead of a chemical dosage (MgCl2) within a circular economy approach. Different Mg/P (1.8:1; 2:1; 3:1) ratios and different TS contents (TS 3.5 and 4.5 %) were studied. The maximum P recovery of 85 % and N recovery of 52 % was obtained at 4.5 % of TS and Mg/P ratio of 2:1, corresponding to an overall P and N recovery on the raw digestate of 70 % and 46 %, respectively. The presence of struvite was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM-EDS). Dried samples were then used as fertilizer in agronomic pot tests using Brassica rapa chinensis. Struvite obtained, showed comparable fertilizing properties in comparison with conventional fertilizers in terms of P (Mineral 5.6 ± 0.4; Poultry 5.7 ± 0.2; Struvite 5.9 ± 0.1 g kg−1), N and total biomass content such as chlorophylls ratio. The growth tests confirmed the possible use of struvite recovered as competitive alternative to conventional chemical phosphate fertilizers. The results showed that it can be possible to promote sustainable P recovery from high solids digestates by the combination of crystallizer reactor and Mg-salt byproducts.

A procedure for determining the number and pattern of digestible starch fractions in multiphasic food digestograms.

Plant-based foods are frequently heterogenous systems, containing multiple starch fractions with distinct digestion rate constants. An unbiased determination of the number and digestion pattern of these fractions is a prerequisite for understanding the digestive characteristics of food. A non-linear least-squares procedure based on a conditional selection of simple first-order kinetics or a combination of parallel and sequential kinetics models was developed. The procedure gave robust results fitting manually generated data, and was applied to in vitro experimental digestion data of retrograded rice starches. By correlating fitting parameters with starch structural parameters, it showed that rice starches with a lower amylose content, longer amylose chains, and amylopectin intermediate chains had more digestible starch fractions after long-term retrogradation. This procedure enables the structural basis of starch digestibility and the development of food products with slow starch digestibility to be better understood. © 2022 Society of Chemical Industry.

Effects of different heat processing methods of rapeseed on ruminal and post-ruminal nutrient disappearance

Due to improving the nutritive value of oilseeds and changing their digestion site in ruminants, processing, including heat treatment, seems necessary. The present research was conducted to evaluate the effect of applying heat processing such as roasting, microwaving and autoclaving on nutritive values; the amount and rate of degradability in rumen, and the disappearance of rapeseed nutrients in rumen, post-rumen and total tract. This evaluation was performed using mobile nylon bags techniques; three-step method of digestion and protein CNCPS fraction. A completely randomized design was used to investigate the effect of applying heat processing, and SAS software was used to analyze the data. The field Emission Scanning Electron Microscope was used to monitored the effect of heat treatment on surface of rapeseed. The application of heat processing in this research (roasting, microwaving and autoclaving) had no significant effect on the chemical composition of rapeseed. The results obtained from mobile nylon bags method and three-step digestion method showed that raw rapeseed has the highest disappearance of DM and CP in rumen and therefore has a significant difference with processed seeds (P&lt;0.05). Also, the disappearance of DM and CP of processed rapeseed in intestines was significantly higher than raw seed (P&lt;0.05), and this was higher than other processing for autoclaved rapeseed. According to the results obtained from CNCPS protein fractionation, applying heat processing altering protein fractionation (P&lt;0.05). Applying microwave processing has created cracks in the surface of the rapeseed wall, and this condition was not observed in the wall surface of other heated seeds. In general, it can be said that in addition to increasing the digestibility of rapeseed in the entire gastrointestinal tract, applying heat processing reduces its degradability in the rumen and has increased the disappearance of nutrients in the intestine, that it can be stated the digestion site is altered from rumen to intestine, which can prevent the loss of protein sources in ruminant feed.

Feeding tannins to dairy cows in different seasons improves the oxidative status of blood plasma and the antioxidant capacity of cheese.

The aim of the present study was to assess the dietary supplementation of tannins to grazing dairy cows in 2 seasons characterized by a good quality pasture (spring) or a poor-quality pasture (summer). The effects of dietary tannins were assessed on plasma antioxidant status and cytokines profile and on the antioxidant properties of cheese and cheese in vitro digestates. Fourteen lactating dairy cows were divided into 2 homogeneous groups (n = 7): a control group (CON), and an experimental group (TAN) receiving 150 g/head per day of tannins supplementation. The experiment was performed twice, in spring and in summer. The animals were free to graze on spontaneous pasture (spring) or on dry stubble (summer). Blood was sampled at the beginning (d 0), at the midpoint (d 11), and at the end (d 22) of the trial. Individual cheese was produced before the beginning (d -1) and at the end (d 22) of the trial from the milk collected from each cow. On blood plasma, the reactive oxygen metabolites (ROM), biological antioxidant potential (BAP), nonesterified fatty acids quantification, and cytokines profile in terms of IL-10, IL-8, IL-1β, and IFN-γ were determined. Data on ROM demonstrated that tannins supplementation lowered oxidative stress both in spring and in summer. Accordingly, TAN diet increased BAP levels compared with the CON during summer trial. Thus, feeding tannins resulted in lower ratio between ROM and BAP (oxidative stress index) in both spring and summer. Cytokines' profile showed lower IL-1β values in TAN group at d 22 during spring season, with a concomitant higher IL-10 level, during summer season. Moreover, TAN group had a lower level of IFN-γ in plasma than CON group, both in spring and in summer. On cheese samples, the in vitro digestion was performed and on cheese and cheese digestates (gastric and intestinal digestate) the free radical scavenging antioxidant activity was evaluated. The intestinal digestate fraction registered the highest antioxidant activity compared with cheese and gastric digestate, in both spring and summer seasons. Furthermore, an improvement of the antioxidant property of cheese and cheese digestates was found. Present data demonstrated that tannins supplementation contributed to reduce the oxidative stress of lactating dairy cows and showed an increase of anti-inflammatory cytokines ratio.

Steam explosion processing intensifies the nutritional values of most crop byproducts: Morphological structure, carbohydrate-protein fractions, and rumen fermentation profile

To investigate the feasibility of steam explosion on the exploitation of ruminant feedstuff, the morphological structure, carbohydrate-protein fractions, and rumen fermentation profile of five typical crop byproducts (corn cob, rice straw, peanut shell, millet stalk, and sugarcane tip) were analyzed before and after steam explosion processing. The results showed that these crop byproducts had different physicochemical properties and rumen fermentation profiles, most of which could be improved by steam explosion processing, i.e., more rough morphological surface, much-broken structure, more digestible carbohydrate fraction (non-NDF +49.92-452.24%), faster gas production rate (c +9.72-68.75%), higher dry matter digestibility (DMD48 +11.38-47.36%), more available energy (ME -3.69-+42.13%, except for peanut shell), along with more unavailable protein fraction (ADICP +27.16-102.70%). It is suggested that steam explosion processing could intensify the feeding value of most crop byproducts for ruminants, but with a caution of heat damage to proteins.