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This study examined the impact of live bread yeast (Saccharomyces cerevisiae) on the nutritional characteristics of Asian dried noodles. Micronutrient analysis of fermented noodles revealed a 6.9% increase in the overall amino acid content, a 37.1% increase in the vitamin B content and a 63.0% decrease in the phytic acid level. Molecular weight analysis of starch and protein contents revealed moderate decrease in the fermented noodles. The in vitro digestion of fermented noodles showed a slightly faster initial acidification, four-fold decrease in the initial shear viscosity (from 8.85 to 1.94 Pa·s). The initial large food particle count (>2 mm diameter) was 19.5% lower in the fermented noodles. The fermented noodles contained slightly higher free sugar content (73.5 mg g-1 noodle) during the gastric digestion phase. The overall nutrition and digestion results indicate nutritional improvement and digestion-easing attributes in the fermented noodles.

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This study focused on the physicochemical properties and tenderness of vacuum-packaged beef M. semitendinosus as affected by various dilution ratios (DRs, 1:4, 1:2, and 1:1) of green kiwifruit juice extract (GKJE) with phosphate buffer during storage at 4°C for 7 days. In addition, the formation of peptides with antioxidant activity for GKJE ability to hydrolyze proteins present in beef was evaluated at different steps of in vitro digestion. Beef with GKJE showed higher tenderness than control (CTL, beef with brine solution alone) during storage, and the increased DR increased tenderness as compared to lower DRs. The addition of GKJE increased protein digestibility during in vitro digestion. To increase the antioxidant activity in the body, GKJE having a DR of 1:2 and 1:1 should be applied to the beef muscle with effective antioxidant activity. These results suggest that DRs of phosphate buffer and kiwifruit juice of 1:1 and 1:2 have the potential to be used as a meat-tenderizing agent and could increase the digestibility of meat as well as the antioxidant capability of bioactive peptides. PRACTICAL APPLICATION: The dilution ratio of kiwi juice with phosphate buffer at 1:1 has the potential to be used as a meat-tenderizing agent during refrigerated storage and also increase the digestibility of beef.

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Lauric acid (LA) has the possibility to improve milk production in dairy cows by improving mammary gland development, however, the mechanism by which it might regulate mammary gland development is unclear. The influence of LA on milk production, nutrient digestibility and the expression of proteins related to mammary gland development in dairy cows were evaluated. Forty primiparous Holstein dairy cows were divided into 4 groups in a randomized block design. Four treatments included the control (0 g/d LA per cow), low-LA (100 g/d LA per cow), medium-LA (200 g/d LA per cow), and high-LA (300 g/d LA per cow). Yields of milk, fat-corrected milk, and energy-corrected milk quadratically increased (P < 0.05), and yield and content of milk fat linearly increased (P < 0.05) with LA supplementation. Percentages of C12:0, C18:1 and C20:1 fatty acids in milk fat linearly increased (P < 0.05), but that of C16:0 fatty acid linearly decreased (P = 0.046). Supplementation of LA led to a linear and quadratical increase (P < 0.05) in digestibility of dry matter, organic matter, neutral detergent fibre and acid detergent fibre, and ruminal total volatile fatty acid concentration but a linear reduction (P = 0.018) in the ratio of acetate to propionate. The enzymatic activities of ruminal pectinase, xylanase, and α-amylase, and populations of total bacteria and anaerobic fungi increased linearly (P < 0.05), while populations of total protozoa and methanogens decreased linearly (P < 0.05) with increased LA addition. Following LA addition, blood glucose, triglyceride, estradiol, prolactin, and insulin-like growth factor 1 concentrations increased linearly (P < 0.05) and albumin and total protein concentrations increased quadratically (P < 0.05). Moreover, addition of 200 g/d LA promoted (P < 0.05) the expression of protein involved in mammary gland development and fatty acids synthesis. These results suggested that LA addition enhanced milk production and fatty acids synthesis by stimulating nutrient digestion, the expression of proteins associated with milk fat synthesis and mammary gland development.

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The incidence of pre-diabetes and diabetes has been increasing recently worldwide and considered as a major growing non-communicable disease. Millets are eco-friendly crops which could sustain extensive climatic conditions. The productivity of millets had increased in recent years to meet the nutritional needs of the increasing global population. The factors which affect the starch digestibility pattern in millets are protein, fat, resistant starch, dietary fibre, and anti-nutrients. However, the interplay of these components also affects the starch digestibility pattern in millets during various processing methods such as thermal, non-thermal, chemical, and their combination. The incorporation of native and processed millet in food products varies the in-vitro and in-vivo glycaemic index. The current study further discusses the potential applications of millet in food formulations for pre-diabetic and diabetic population. Hence the appropriately processed millets could be a suggested as a suitable dietary option for pre-diabetic and diabetic population.

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The aim of this study is to determine the effect of the digestibility of cassava starch by the enzymes extracted from corn malt, which will constitute one of the answers to the problem of integrating local products into the process in a modern brewery. Cassava starch solutions of different concentrations (E0: 0 g/L; E1: 1 g/L; E2: 1.1 g/L; E3: 1.2 g/L; E4: 1.3 g/L; E5: 1.4 g/L and E6: 1.5 g/L) were prepared and subjected to two treatments (gelatinized and non-gelatinized) and 5 mL of each were placed in a test tube. Three millilitres (3 mL) of the solution containing amylases extracted from malt corn was then added to each of the test tubes containing the cassava flour solutions. All the treatments were subjected to three temperature stages (50 °C for 15 min, 90 °C for 20 min, and 100 °C for 75 min). Twenty-eight (28) objects (two duplicates) were experimented in a complete factorial design (2 treatments × 2 temperature levels). The results obtained showed that gelatinization had no effect, which could be due to the high optimum temperatures of corn enzyme activity. The concentrations also did not have significant differences which shows that these concentrations can well be used on an industrial scale to digest cassava starch by corn malt enzymes.

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The extrusion process, a vital technique for starch modification, is notably influenced by the moisture content (MC). This study aimed to elucidate the effect of varying MC levels (18, 22, 26, and 30%) on the structural and physicochemical characteristics of cassava flour during extrusion. Extrusion resulted in the fraction of degree of polymerization 13‒24, degree of branching, and molecular weight increased with increasing MC, with values of above indexes being 32.29%, 1.05%, and 1.21 × 105 g/mol, respectively, at a MC of 18%. This suggested that the degradation of amylopectin and amylose. Additionally, there was an increase in rapidly digestible starch (RDS) and a decrease in slowly digestible starch (SDS) in the extrudates in comparison to the native cassava flour. The extrusion of cassava flour at 18% MC exhibited the highest levels of RDS and SDS, reaching 64.52% and 4.06%, respectively. These findings indicated that low moisture extrusion could be a more effective method for disrupting the structure of cassava starch and enhancing the digestibility of cassava flour, offering valuable insights for the optimized use of cassava extrudates in various applications.

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Duckweed has attracted increasing attention as a high-quality and sustainable novel plant-based protein source. However, little research has been conducted in dogs and cats. We evaluated the effects of inclusion of duckweed protein (Lemna; MCSelect; Parabel; Vero Beach, FL) primarily in replacement of pea protein in dog diets at 0%, 5%, and 10% and cat diets at %, 10%, and 15% on stool quality, nutrient digestibility, and palatability. We hypothesized that duckweed protein would be a viable protein source in both dog and cat diets by showing no detriment to nutritional outcomes. All feeding tests were conducted at an independent research facility (Susquehanna, PA). A standard 2-bowl palatability test over a 2-d period was conducted with adult animals (n = 30 each) to determine intake ratio between test diets (duckweed-containing diets) and control diets (0% duckweed protein). Apparent total tract nutrient digestibility was conducted with 18 adult dogs and 21 adult cats (n = 6 to 7 per diet) with 5 d of diet acclimation followed by 5 d of total fecal collection. Stool quality was evaluated on a 1 to 5 scale where 1 = non-formed or diarrhea and 5 = hard, formed. Palatability data were analyzed using paired t-test (daily consumption) and chi-square test (first choice). All other data were analyzed by ANOVA and contrast (SAS version 9.4). For cats, 10% duckweed had greater (P < 0.05) palatability than control, while no difference was observed between 15% duckweed protein and control. For dogs, 5% and 10% duckweed protein had (P < 0.05) lower palatability, demonstrating a preference to control. Both cats and dogs fed duckweed diets had acceptable stool quality (Mean = 3.4 and 3.3, respectively). No detriments in nutrient digestibility were observed in dogs fed 5% and 10% duckweed protein; however, cats fed 10% and 15% duckweed protein had (P < 0.05) lower dry matter, protein, and energy digestibility vs. control. In conclusion, the data collected indicate that duckweed can be a viable replacement for other plant-based proteins in dog diets at inclusion levels up to 10%; more development is needed for duckweed protein inclusion into cat diets.

Duckweed, an aquatic plant rich in protein, holds promise as a sustainable plant-based protein for companion animals. However, the potential of duckweed protein in dog and cat diets has been relatively unexplored. In our study, we assessed the viability of incorporating duckweed protein into dog and cat diets by examining nutrient digestibility, stool consistency, and diet palatability. Our findings indicate that including duckweed protein in dog diets maintains acceptable nutrient digestibility and improves stool quality, although it may impact diet palatability. For cats, duckweed protein inclusion led to reduced nutrient digestibility, looser stool, and lower diet palatability. While duckweed protein shows potential as a suitable plant-based protein source for dogs, further development is necessary before considering it for cat diets.

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This experiment aimed to study the effects of tannin supplementation on growth performance, rumen fermentation characteristics, apparent digestibility and serum biochemistry, and antioxidant and immune indexes in fattening lambs. A total of 36 male Hu sheep lambs (body weight = 15.83 ± 0.48 kg and days of age = 55 ± 2 d) were fed a high-concentrate diet and randomly divided into one of three groups of 12 animals each: control with no tannin (CON) and tannin treatments (TA1, 3 g/d per lamb; TA2, 6 g/d per lamb). The feeding experiment lasted for 60 d. The results showed that the average daily gain and ruminal propionate content of lambs in the TA1 group were higher (p < 0.05) than those in the CON group. Lambs fed tannin had significantly increased (p < 0.05) microbial protein and decreased (p < 0.05) ammonia nitrogen concentrations in the rumen. In addition, the crude protein and neutral detergent fiber digestibility of the TA2 group were significantly decreased (p < 0.05) as compared with the TA1 and CON groups, respectively. The serum concentrations of triglyceride, immunoglobulin A, and catalase and the total antioxidant capacity were higher (p < 0.05) in the TA1 group that those in the CON group, whereas an opposite trend of urea nitrogen, interleukin-1ß, and malondialdehyde was found between the two groups. Also, tannin supplementation increased (p < 0.05) Lactobacillus and decreased (p < 0.05) Salmonella counts in the feces of lambs. Taken together, tannin supplementation can improve the growth performance, immunity, and antioxidant ability of fattening lambs fed a high-concentrate diet.

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This study aimed to investigate the effects of different defatting methods of black soldier fly (Hermetia illucens) larvae meal (BSFM) on the metabolic energy and nutrient digestibility in laying hens. Sixty young laying hens (Hy-Line W-36) aged 63 days were randomly divided into two groups (G1 and G2), each with five replicates of six hens housed in individual cages. Group G1 was fed 25% pressed black soldier fly meal (BSFMp) and 75% basal diet, and Group G2 was fed 25% extracted black soldier fly meal (BSFMe) and a 75% basal diet. Both diets included 5 g/kg chromium oxide as an external marker. A 7-day preliminary trial was followed by a 4-day experimental period. The results indicate that pressing and extracting significantly affected the digestibility of crude fat and total energy in BSFM, with BSFMp showing significantly higher crude fat digestibility than BSFMe. Similarly, total energy digestibility was also significantly higher in BSFMp. However, there were no significant differences in dry matter, organic matter, and crude protein digestibility between the two processing methods. The apparent metabolic energy values of BSFMp and BSFMe were 16.34 and 12.41 MJ/kg, respectively, showing a significant difference. The nitrogen-corrected metabolic energy values were 15.89 MJ/kg in BSFMp and 11.93 MJ/kg in BSFMe, indicating a highly significant difference. The digestibility of arginine and leucine in BSFMp was significantly higher than in BSFMe, while differences in lysine, cystine, threonine, tryptophan, and isoleucine were not significant. In conclusion, both defatting methods of BSFM had no adverse effects on the metabolic energy and nutrient digestibility in young laying hens, but BSFMp demonstrated better effects on the digestibility of metabolic energy and nutrients in the feed for young laying hens.

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This study aimed to determine the standardized ileal digestibility (SID) of calcium (Ca) and phosphorus (P) in various feed ingredients using the direct method. This study comprised eight experimental diets: a Ca-P-free diet and seven experimental diets, each containing monocalcium phosphate (MCP), dicalcium phosphate (DCP), monosodium phosphate (MSP) + limestone, corn, and soybean meal (SBM) as the sole sources of Ca and/or P. These diets provided 4.21 g/kg of non-phytate P from MCP, DCP, or MSP, and the MSP + limestone diet included 7.50 g/kg of Ca. The corn and SBM diets formulated to determine P digestibility maintained a dietary Ca/total P ratio of 1.4 through the addition of limestone. Chromic oxide was added to the diets as an indigestible index. On day 18, 256 male and 256 female broilers were individually weighed and randomly assigned to eight treatments, each with four replicates for each sex (eight birds per cage). This allocation followed a randomized complete block design based on body weight. On day 21, the birds were euthanized using carbon dioxide, and ileal digesta samples were collected from the distal two-thirds section of the ileum. No significant interactions between the experimental diets and sex regarding the SID of Ca or P were detected, and no effect of sex on the SID was observed. The standardized ileal Ca digestibility of MCP, DCP, limestone, corn, and SBM was found to be 84.7%, 70.1%, 52.6%, 88.6%, and 81.6%, respectively. The standardized ileal P digestibility of MCP, DCP, MSP, corn, and SBM was determined to be 91.8%, 76.8%, 94.4%, 73.1, and 88.4%, respectively. Given the variable digestibility of Ca and P across different feed ingredients, the consideration of the specific type of ingredients used in diet formulation is crucial.

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The effect of including micronised fibre sources (FS) differing in fermentability and hydration capacity (HC) on growth performance, faecal digestibility, and caecal fermentation was investigated in piglets. There were four dietary treatments: a control diet (CON) and three treatments differing in the HC and fermentability of FS added at 1.5% to prestarter (28-42 d) and starter (42-61 d) diets. These were: LHC (low-HC by-product-based insoluble fibre (IF) with a prebiotic fraction (PF) from chicory root); MHC (medium-HC by-product-based IF with a PF); and HHC (high-HC non-fermentable wood-based IF with no PF). There were eight replicates per treatment. Over the entire period, LHC and MHC piglets showed a 10% increase in daily growth and feed intake (p ≤ 0.019) and tended to have a reduced feed conversion ratio (p = 0.087) compared to HHC piglets. At 42 d, faecal protein digestibility increased by 5% in the LHC and MHC groups compared with the HHC group (p = 0.035) and did not differ from the CON group. Both LHC and MHC fibres were more fermented in vitro with caecal inocula from 61 d old piglets than HHC fibre (p ≤ 0.003). These results suggest that balanced soluble and insoluble fibre concentrates can improve piglet performance.

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Weizmannia coagulans is increasingly employed in food processing owing to its health benefits. Our previous research developed Oolong tea-fortified rice noodles with unique flavor and potent antioxidant activity; however, their texture still requires improvement. In this study, Oolong tea-fortified rice noodles were fermented using W. coagulans PR06 at inoculation amounts of 1%, 3%, and 5% (v/v), and assessed for cooking quality, texture, and starch digestibility. The results indicated that fermentation with 3% and 5% W. coagulans PR06 altered the amylopectin length distribution in the rice noodles and increased the degree of starch short-range order. Furthermore, the fermentation process increased the storage modulus (G') and loss modulus (G″) values, decreased the tan δ value, and strengthened the interactions among tea polyphenols, proteins, and starch in the rice flour gel. Consequently, this process increased the hardness and chewiness of the rice noodles, decreased their broken strip rate and cooking loss, and significantly reduced their in vitro starch digestibility. Overall, fermentation with W. coagulans PR06 markedly improved the texture and cooking quality of Oolong tea-fortified rice noodles while effectively delaying starch digestion. This study highlights the potential application of W. coagulans PR06 in developing diverse and functional rice noodle products.

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Heat-moisture treatment (HMT) is a widely used method for modifying starch properties with the potential to reduce the digestibility of high-amylose starch (HAS). This study aimed to optimize the HMT conditions for HAS and apply the resulting HMT-HAS to triticale noodles to develop low-glycemic-index products. HMT significantly increased the resistant starch (RS) content and decreased the rapidly digestible starch (RDS) content of HAS. The treatment conditions-temperature, heating time, and moisture content-were found to significantly influence the starch composition. Optimal HMT conditions were determined using response surface methodology: a temperature of 108 °C, a heating time of 5.8 h, and a moisture content of 25.50%. Under these conditions, the RS content of HMT-HAS was 60.23%, nearly double that of the untreated sample. Increasing the level of HMT-HAS in triticale noodles led to significant decreases in short-range order, relative crystallinity, and viscosities, while the RS content increased from 12.08% to 34.41%. These findings suggest that incorporating HMT-HAS into triticale noodles effectively enhances starch digestive resistance, supporting the development of functional, low-glycemic-index triticale-based foods.

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The physical modification of starch to produce resistant starch (RS) is a viable strategy for the glycemic index (GI) lowering of foods and functionality improvement in starchy food products. RS cannot be digested in the small intestine but can be fermented in the colon to produce short-chain fatty acids rather than being broken down by human digestive enzymes into glucose. This provides major health advantages, like better blood sugar regulation, weight control, and a lower chance of chronic illnesses. This article provides a concise review of the recent developments in physical starch modification techniques, including annealing, extrusion, high-pressure processing, radiation, and heat-moisture treatment. Specifically, the focus of this paper is on the alteration of the crystalline structure of starch caused by the heat-moisture treatment and annealing and its impact on the resistance of starch to enzymatic hydrolysis, as well as the granular structure and molecular arrangement of starch caused by extrusion and high-pressure processing, and the depolymerization and crosslinking that results from radiation. The impacts of these alterations on starch's textural qualities, stability, and shelf life are also examined. This review demonstrates how physically modified resistant starch can be used as a flexible food ingredient with both functional and health benefits. These methods are economically and ecologically sustainable since they successfully raise the RS content and improve its functional characteristics without the need for chemical reagents. The thorough analysis of these methods and how they affect the structural characteristics and health advantages of RS emphasizes the material's potential as an essential component in the creation of functional foods that satisfy contemporary dietary and health requirements.

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The developmental changes in the granular surface structure and functional properties of starch during the entire grain filling period of rice (around 40 days) were investigated. The specific surface area of rice starch significantly decreased firstly then stabilized during growth due to increasing granular size. The pore volume decreased from 5.40 cm3/g at 6th day after anthesis (DAA-6) to 3.02 cm3/g (DAA-46). More starch granule-associated proteins (SGAPs) accumulated on the surface and in channels. Swelling power decreased by 46 %, whereas the flow behavior index (n) decreased by 32 % in upward curve during starch development from DAA-6 to DAA-30. Tan δ first dropped then remained steady at DAA 22-34 and lightly rebounded at the final stage, indicating that starch in the middle stage tended to have greater viscoelastic gel behavior at all sweeps. Mature starch showed lower in vitro hydrolysis rate and exhibited stronger enzymatic resistance. The results showed that granular surface features of rice starch may be an essential factor in determining rheological behavior and resistance to hydrolysis.

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BACKGROUND: Addressing the shortage of high-quality protein resources, this study was conducted to investigate the effects of replacing soybean meal (SBM) with different levels of enzymolysis-fermentation compound protein feed (EFCP) in the diets of growing-finishing pigs, focusing on growth performance, nutrients digestibility, carcass traits, and meat quality. METHODS: Sixty DLY (Duroc × Landrace × Yorkshire) pigs with an initial body weight of 42.76 ± 2.05 kg were assigned to 5 dietary treatments in a 2 × 2 + 1 factorial design. These dietary treatments included a corn-soybean meal diet (CON), untreated compound protein feed (UCP) substitution 50% (U50) and 100% SBM (U100) diets, and EFCP substitution 50% (EF50) and 100% SBM (EF100) diets. Each treatment had 6 pens (replicates) with 2 pigs per pen, and the experiment lasted 58 d, divided into phase I (1-28 d) and phase II (29-58 d). Following phase I, only the CON, U50, and EF50 groups were continued for phase II, each with 5 replicate pens. On d 59, a total of 15 pigs (1 pig/pen, 5 pens/treatment) were euthanized. RESULTS: During phase I, the EF50 group had a higher average daily gain (ADG) in pigs (P < 0.05) compared to the CON group, whereas the U50 group did not have a significant difference. As the substitution ratio of UCP and EFCP increased in phase I, there was a noticeable reduction in the final body weight and ADG (P < 0.05), along with an increase in the feed-to-gain ratio (F/G) (P < 0.05). In phase II, there were no significant differences in growth performance among the treatment groups, but EF50 increased the apparent digestibility of several nutrients (including dry matter, crude protein, crude fiber, acid detergent fiber, ash, gross energy) compared to U50. The EF50 group also exhibited significantly higher serum levels of neuropeptide Y and ghrelin compared to the CON and U50 groups (P < 0.05). Moreover, the EF50 group had higher carcass weight and carcass length than those in the CON and U50 groups (P < 0.05), with no significant difference in meat quality. CONCLUSIONS: The study findings suggest that replacing 50% SBM with EFCP during the growing-finishing period can improve the growth performance, nutrient digestibility, and carcass traits of pigs without compromising meat quality. This research offers valuable insights into the modification of unconventional plant protein meals and developing alternatives to SBM.

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In this study, the structural characteristics, functional properties, and in vitro gastrointestinal digestibility of glutenin from Tiger nut seed meal (TNSMG) treated by microwave (140-700 W, 20-60 s) and water-bath heating (40-100 °C, 10-30 min) were investigated. Analysis of the surface hydrophobicity, intrinsic fluorescence spectroscopy and Fourier transform infrared spectroscopy indicated that both microwave and water-bath heating treatments caused structure changes of TNSMG. The results showed an increase in the exposure of sulfhydryl groups and the content of ß-sheet, coupled with a decrease in the content of α-helix and ß-turn. These structural changes contributed to the improved solubility, foamability, emulsification properties, and digestibility of TNSMG under proper thermal treatment conditions. TNSMG exhibited the best solubility (68.48%) and foamability (85.56%) after water-bath heating treatment for 20 min at 80 °C. Furthermore, TNSMG showed the best emulsification property (9.61 m2/g) and digestibility (78.58%) when treated by microwave treatment at 560 W for 40 s.

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The digestion of starch have been of great interest, yet little is known about the structure changes and structure-digestibility relationships of waxy rice starch during digestion. In this study, waxy rice starch from Indica and Japonica cultivars were in vitro pre-digested for different times, and the changes in their structure and properties were investigated, including granule morphology, chain length distribution, short-range ordered structure, crystallinity, thermal properties, and digestibility. Pre-digested Indica and Japonica waxy rice starch had the characteristics of porous starch, showing similar surface erosion and pores. With the prolongation of pre-digestion time, the amylose content decreased by 0.74 %-2.69 %, the proportion of amylopectin short A chain (DP6-12) and B1 chain (DP13-24) decreased, and the proportion of long B2 (DP25-36) and B3 chain (DP ≥ 37) increased, especially in pre-digested Indica waxy rice starch. The short- and long-range ordered structure of pre-digested starch increased, manifested by an increase in the absorbance ratio at 1047/1022 cm-1, a decrease at 1022/995 cm-1, and an increase in relative crystallinity, leading to higher gelatinization temperature and enthalpy. Pre-digested waxy rice starch had a reduced rapidly digestible starch of 18.27 %-33.93 % and an increased resistant starch of 29.51 %-41.32 %, which will be applied in functional starch and healthy starchy foods.

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The changing global climate brings a gradual yet constant and adverse shift in crop production. Grain crop plants, particularly cereals and legumes, respond varyingly to adverse climate, including reduction in grain yield and changes to their nutrient densities. An understanding of specific changes to crop systems under differing climatic conditions can help in planning diets to meet human nutrient sufficiency. Grain protein content is also affected by adverse environmental factors. Deficits in protein yield, linked to changes in grain or seed protein and antinutrient concentrations, have been reported in major food crops when exposed to elevated carbon dioxide, high temperature, drought, and humidity. These changes, in addition to affecting the quantity of indispensable or essential amino acids (IAA), also impact their bioavailability. Therefore, it is important to assess consequences of climate change on grain protein quality. An important tool to measure grain protein quality, is measuring its digestibility at the level of the ileum and its IAA concentration, linked to a metric called the Digestible IAA Score (DIAAS). A minimally invasive technique called the dual isotope tracer technique, which measures IAA digestibility after simultaneous administration of two different intrinsically labelled protein sources, one a test protein (2H/15N) and one a reference protein (13C) of predetermined digestibility, has been used in evaluation of grain protein IAA digestibility, and promises more in the evaluation of changes based on climate. This review discusses climate induced changes to grain protein quality through the prism of IAA digestibility, using the dual isotope tracer technique.

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BACKGROUND: Phytogenic additives would be helpful to alleviate the adverse effect of Campylobacter jejuni on the performance and physiological responses of broiler chickens. OBJECTIVE: This experiment was carried out to investigate the effects of Echinacea purpurea (EP) and Thymbra spicata (TS) on the performance, nutrient digestibility, serum biochemistry, intestinal morphology, intestinal microbiota and immune responses of broilers challenged with C. jejuni from 0 to 42 days of age. METHODS: A total of 240 male broiler chickens were divided into 6 groups and fed various diets: a control diet; the control diet supplemented with EP at 0.25% (EP25) or 0.50% (EP50); the control diet supplemented with TS at 0.25% (TS25) and 0.50% (TS50); or the control diet containing erythromycin at 55 ppm. Chicks were orally challenged with C. jejuni on Days 21 and 23 of age. RESULTS: EP and TS25 diets enhanced European production efficiency factor, feed conversion ratio and digestibility of dry matter and organic matter. TS25 increased duodenal villous height (VH) and surface area on Day 42 of age. EP25 diet increased ileal VH compared to control and erythromycin diets. Diets containing certain EP25 and TS increased the Bifidobacterium population and decreased C. jejuni population on Day 39 of age. EP50 and TS50 diets increased antibody titration against Newcastle disease virus. CONCLUSIONS: In conclusion, EP and TS dietary supplementation improved performance, microflora, intestinal morphology and immune responses in C. jejuni-challenged broilers.

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