Extrusion puffing as a pretreatment method to change the surface structure, physicochemical properties and in vitro protein digestibility of distillers dried grains with solubles.

BACKGROUND: Distillers dried grains with solubles (DDGS) are rich in nutrition, and they are potential protein feed raw material. However, the existence of cellulose, hemicellulose and lignin hinders animals' digestion and absorption of DDGS. Making full use of unconventional feed resources such as DDGS can alleviate the shortage of feed resources to a certain extent. This research investigated the effects of twin-screw extrusion on the macromolecular composition, physical and chemical properties, surface structure and in vitro protein digestibility (IVPD) of DDGS. RESULTS: The findings showed that extrusion puffing significantly increased the protein solubility, bulk density, water holding capacity, and swelling capacity, while significantly decreased hemicellulose and crude protein content, particle size and zeta potential of DDGS. The structure damage of DDGS induced by the extrusion was characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FITR) spectroscopy and X-ray diffraction (XRD) analysis. Interestingly, no random coil was observed in the analysis of the secondary structure, and extrusion promoted the transformation of α-helix and ß-turn to ß-sheet, which led to significant increases in protein solubility and IVPD of DDGS (P < 0.05). Additionally, correlation analysis revealed that IVPD and PS had a positive relationship. CONCLUSION: Extrusion puffing was an ideal pretreatment method for DDGS modification to improve in vitro protein digestibility. © 2023 Society of Chemical Industry.

Influences of grain and protein characteristics on in vitro protein digestibility of modern and ancient wheat species.

BACKGROUND: The resistance of proteins to gastrointestinal digestion contributes to their ability to act as allergens. Near-complete digestion of protein in wheat products is important with respect to avoiding the potential immunogenic effects of undigested peptides. Five modern US wheat classes (soft red winter, hard winter, hard red spring, club and durum) including 17 wheat varieties, as well as three ancient wheat classes (spelt, emmer and einkorn) including nine wheat varieties, were analyzed for kernel hardness (KH) and flour protein characteristics, in addition to in vitro protein digestibility (IVPD) of cooked flour, flour without albumins and globulins (FWOAG), gluten, albumins, and globulins, aiming to identify the factors influencing the protein digestibility of flour. RESULTS: IVPDs of flour, FWOAG, gluten and albumins of wheat varieties ranged from 86.5% to 92.3%, 85.8% to 90.3%, 90.6% to 94.6% and 74.8% to 85.1%, respectively. The IVPD of gluten was significantly higher than the IVPDs of flour and FWOAG, indicating that non-protein components substantially affect protein digestibility. Significant differences were observed in IVPDs of flour and albumins among eight wheat classes, but not in the IVPDs of FWOAG, gluten and globulins. There were apparent differences in undigested protein bands and intensities of wheat classes with low and high flour IVPDs. KH and albumin proportion exhibited negative and positive relationships, respectively, with flour IVPD. CONCLUSION: The results of the present study demonstrate that KH, non-protein components and albumin proportion have a major influence on protein digestion and need to be considered when developing wheat cultivars with higher protein digestibility.

In vitro protein digestibility of finger millet complementary porridge as affected by compositing precooked cowpea with improved malted finger millet.

Protein-energy malnutrition is one of the leading causes of death for children under-five in developing countries and Kenya is no exception. These children rely on starchy weaning foods such as finger millet (Eleusine coracana), which have poor protein digestibility. Cowpea (Vigna unguiculata), a locally available nutritious legume, could be an excellent complement to lysine-deficient millet diets. The present study thus aimed at innovatively improving protein digestibility of a baby weaning food, by evaluating the effect of malting on improved finger millet genotypes (U15, P224, KNE741, KNE629 and Snapping green) to enable selection of the best varieties with superior nutritional credential post process. Blending of selected finger millet with precooked cowpea flour followed the WHO recommended level at 10.32%, 21.26%, and 32.75% with 0% as control. Extractable phenols, condensed tannins, phytic acid, protein content, and protein digestibility were determined using recommended methods. Extractable phenol, condensed tannin, and phytate notably decreased by 44%, 47%, and 29% respectively after malting. Additionally, compositing with precooked cowpea increased protein content and protein digestibility in flour by about 6-39%. Cooking resulted in a 10% increase in protein digestibility in the complementary porridge. Malting of finger millet and compositing it with precooked cowpea has the potential to address PEM as it results in reduced anti-nutritional content with a concomitant improvement in protein digestibility of the baby weaning food.

Preparation of horsegram protein concentrate with improved protein quality, in vitro digestibility and available lysine.

Horsegram (Macrotyloma uniflorum or Dolichos biflorus), an inexpensive pulse crop with high lysine and iron contents, is underutilized due to the presence of antinutrients like lectin and trypsin inhibitors, which limit protein digestibility and availability. Horsegram protein concentrate (HGPC) was prepared, which had 80.4 ± 3.5% protein and 94.2 ± 1.4% in vitro protein digestibility compared to dehulled horsegram flour (22.8 ± 0.8% and 82.3 ± 1.2%, respectively). Available lysine content in concentrate was increased by 64% compared to dehulled horsegram flour. The trypsin inhibitory activity in the protein concentrate decreased by 51% from 36.6 ± 3.5 TIU/mg in horsegram flour to 17.6 ± 2.5 TIU/mg in HGPC. Nutritional indices, including PDCAAS values for different age groups, were calculated and found to be slightly lower due to the loss of methionine and tryptophan in the concentrate. However, branched amino acids and lysine contents were higher. Thus, a vegetarian source with high protein digestibility and available lysine content could be prepared as a protein ingredient for the food industry.

Influence of multigrain premix on nutritional, in-vitro and in-vivo protein digestibility of multigrain biscuit.

Effect of addition of multigrain premix (MGP) prepared using a combination of cereals, pulses and oilseeds at 40% level, on nutritional properties of multigrain biscuit, its in-vitro and in-vivo protein digestibility and protein profiling were studied. The incorporation of MGP significantly increased the protein content (from 7.37 to 16.61%), insoluble dietary fiber (from 1.71 to 6.67%), soluble dietary fiber (from 0.46 to 2.42%). The significant increase in the levels of isoleucine (ND-34.79%), methionine (0.04 to 7.65%), tryptophan (0.22 to 5.95%) valine (0.38 to 16.58%), lysine (0.36 to 7.32%), and threonine (0.51 to 7.2%) was observed, whereas fatty acid profile of MGP incorporated biscuits showed increased polyunsaturated fatty acids and decreased saturated fatty acids. The vitamin-mineral profile of MGP incorporated biscuits showed increased the thiamin (0.07-0.21 mg/100 g), riboflavin (0.09-0.28 mg/100 g), calcium (12.89-45.28 mg/100 g) and iron (1.13-3.47 mg/100 g) contents. The in-vitro protein digesibility of multigrain and control biscuits indicated that the proteins present in multigrain biscuits had high digestibility (71.73%) as compared to control biscuit (38.13%). The in-vivo studies indicated that, the protein quality of multigrain biscuits was comparable with casein protein with high protein efficiency ratio of 3.02. The electrophoretic pattern of multigrain biscuits showed subunit molecular weight distribution of different protein units and aggregation of protein bands at high molecular weight region of 85 to 166 kD. The outcome of the study indicated the possibility of utilising MGP to improve the overall nutritional quality of biscuits.

Biochemical diversity evaluation in chickpea accessions employing mini-core collection.

The seeds of chickpea provide an exceptional source of dietary proteins and is one of the important legumes in both developed and developing countries over the world. The available germplasm of cultivated chickpea is deficient in desired biochemical signatures. To identify new sources of variations for breeding, reduced subsets of germplasm such as mini-core collection can be explored as an effective resource. In the present investigation, mini-core collections consisting of 215 accessions of chickpea were extensively evaluated for tapping biochemical diversity. Analysis included ten biochemical parameters comprising total protein, total free amino acids, phytic acid, tannin, total phenolics, total flavonoids, lectin, DPPH radical scavenging activity, in vitro digestibility of protein and starch. The spectrum of diversity was documented for total protein (4.60-33.90%), total free amino acids (0.092-9.33 mg/g), phytic acid (0.009-4.06 mg/g), tannin (0.232-189.63 mg/g), total phenolics (0.15-0.81 mg/g), total flavonoids (0.04-1.57 mg/g), lectin (0.07-330.32 HU/mg), DPPH radical scavenging activity (26.74-49.11%), in vitro protein digestibility (59.45-76.22%) and in vitro starch digestibility (45.63-298.39 mg of maltose/g). The principal component analysis revealed association of chickpea higher protein content to the lower level of total phenolics and flavonoid contents. The dendrogram obtained by unweighted pair group method using arithmetic average cluster analysis grouped the chickpea accessions into two major clusters. This is the first comprehensive report on biochemical diversity analysed in the mini-core chickpea accessions. The ultimate purpose of conducting such studies was to deliver information on nutritional characteristics for effective breeding programmes. Depending on the objectives of the breeding aforesaid accessions could be employed as a parent.

The Potential Use of Fermented Chickpea and Faba Bean Flour as Food Ingredients.

Apart from being a rich and inexpensive protein source, legumes provide essential vitamins, minerals and dietary fibre. Considering the nutritional benefits, legumes flour can potentially be incorporated in the development of new products. The aim of this study was to investigate whether fermentation affects the protein content, in vitro protein digestibility, trypsin inhibitor activity and the functionality of proteins in faba bean, desi and kabuli chickpea. Australian grown chickpea and faba bean were selected and initially soaked, de-hulled, dried and milled into flour. This was fermented with lyophilised yoghurt cultures in a 30 °C orbital shaker for 16 h. While protein contents in fermented desi and kabuli flour were lower than their raw counterparts (p > 0.05), it was significantly higher in fermented faba bean. A significant increase (9.5%) in in vitro protein digestibility was found in fermented desi. Trypsin inhibitor activity in fermented desi, kabuli and faba bean reduced by 2.7, 1.1 and 4.7%, respectively (p > 0.05). Overall, the in vitro protein digestibility in flour samples increased, while simultaneously reducing the trypsin inhibitor activity. The water absorption capacity of the fermented kabuli flour significantly increased by 11.3%. All fermented flour samples had significantly higher oil absorption capacity than their corresponding raw flour that was likely due to increased insoluble hydrophobic protein. Although, the foaming capacity in all fermented flour samples was significantly lower than their respective raw samples, only fermented desi and faba bean flour showed lower foaming stability (p > 0.05). The present study suggests that fermented legume flour could fulfill the demand for innovative products of higher nutritional value.

Malting process optimization for protein digestibility enhancement in finger millet grain.

Finger millet (Eleusine coracana) is a nutritious, gluten-free, and drought resistant cereal containing high amounts of protein, carbohydrate, and minerals. However, bio-availability of these nutrients is restricted due to the presence of an excessive level of anti-nutrient components, mainly phytic acid, tannin, and oxalate. It has been shown that a well-designed malting/germination process can significantly reduce these anti-nutrients and consequently enhance the nutrient availability. In the present study, the effects of two important germination factors, duration and temperature, on the enhancement of in-vitro protein digestibility of finger millet were thoroughly investigated and optimized. Based on a central composite design, the grains were germinated for 24, 36, and 48 h at 22, 26, and 30 °C. For all factor combinations, protein, peptide, phytic acid, tannin, and oxalate contents were evaluated and digestibility was assessed. It was shown that during the malting/germinating process, both temperature and duration factors significantly influenced the investigated quantities. Germination of finger millet for 48 h at 30 °C increased protein digestibility from 74 % (for native grain) up to 91 %. Besides, it notably decreased phytic acid, tannin, and oxalate contents by 45 %, 46 %, and 29 %, respectively. Linear correlations between protein digestibility and these anti-nutrients were observed.

Germinated, toasted and cooked chickpea as ingredients for breadmaking.

The effect of processing (germination, toasting and cooking) of chickpea beans was investigated on the resulting flours characteristics and their potential for obtaining gluten free breads. Rheological properties of dough were recorded using Mixolab(®) and breads were analyzed for their instrumental quality, nutritional and sensory properties. Chickpea based doughs showed low consistency and their rheological behavior was defined by the starch gelatinization and gelification. The bread made with cooked chickpea flour exhibited the lowest specific volume (0.58 mL/g), brightest crumb (L* = 76.20) and the softest texture, but cooking decreased the content of carbohydrates, ash and protein, although increased the protein digestibility. The highest specific volume was obtained in bread made with toasted chickpea flour, although crumb hardness was higher. Overall, processing of chickpea beans, concretely toasting and cooking led to flours that could be used for obtaining gluten free breads with the nutritional characteristics of the legumes and acceptable sensory characteristics.

Development of quick cooking multi-grain dalia utilizing sprouted grains.

Multi-grain dalia (MGD) formulations were prepared utilizing sprouted wheat and mixer of other three grains (barley, sorghum and pearl millet) in the ratio of 100:0 (MGD-A), 75:25 (MGD-B), 50:50 (MGD-C), 25:75 (MGD-D) and 0:100 (MGD-E), respectively. The mixer of barley, sorghum and pearl millet was prepared using 50, 25, 25 parts of these grains, respectively. The recovery of grits/ dalia (particle size 1.41 to 2 mm) from sprouted wheat and barley was 74.56 and 69.77 %, respectively while sorghum and pearl millet yield 47.94 and 49.39 % (particle size 0.954 to 1.41 mm), respectively. Sprouting brought a reduction of cooking time by about 50 % as compared to un-sprouted studied grains. Cooking time for different MGD formulations ranged from 3.91 to 4.42 min, which was slightly increased with increasing proportion of mixer of barley, sorghum and pearl millet (p > 0.05). Rehydration ratio of MGD samples varied from 3.12 to 3.45 with minimum in MGD-E sample. Though protein content was decreased with increasing proportion of mixer of three grains in MGD samples but in vitro protein digestibility (58.68 to 62.75 %) was similar (p > 0.05). The mean overall sensory acceptability scores for MGD samples ranged from 7.50 to 8.49 with ≥8.0 in samples having up to 75 % grits of mixer of three grains. In view of very good overall sensory acceptability, rich in crude fibre, calcium and iron content and low cooking time, 25:75 parts of sprouted wheat and mixer of studied three grains, respectively may be considered for preparation of acceptable quality quick cooking multi-grain dalia.

Physico-chemical, nutritional and infrared spectroscopy evaluation of an optimized soybean/corn flour extrudate.

A central composite design using RMS (Response Surface Methodology) successfully described the effect of independent variables (feed moisture, die temperature and soybean proportion) on the specific parameters of product quality as expansion index (EI), water absorption index (WAI), water solubility index (WSI) and total color difference (ΔE) studied. The regression model indicated that EI, WAI, WSI and ΔE were significant (p < 0.05) with coefficients of determination (R(2)) of 0.7371, 0.7588, 0.7622, 0.8150, respectively. The optimized processing conditions were obtained with 25.8 % feed moisture, 160 °C die temperature and 58 %/42 % soybean/corn proportion. It was not found statistically changes in amino acid profile due to extrusion process. The electrophoretic profile of extruded soybean/corn mix presented low intensity molecular weight bands, compared to the unprocessed sample. The generation of low molecular weight polypeptides was associated to an increased in In vitro protein digestibility (IVPD) of the extrudate. The FTIR spectra of the soybean/corn mix before and after extrusion showed that the α-helix structure remained unchanged after extrusion. However, the band associated with ß-sheet structure showed to be split into two bands at 1624 and 1640 cm(-1) . The changes in the ß-sheet structures may be also associated to the increased in IVPD in the extruded sample.

Response surface optimization of enzymatic hydrolysis of duck blood corpuscle using commercial proteases.

With the rapid development in livestock and poultry husbandry and increasing shortage of protein sources, recycling of wastes from agricultural and food processing such as blood corpuscles has been regarded as an important industrial procedure to obtain protein sources. This study aimed to find an appropriate method for recycling the considerable amounts of blood corpuscle so as to improve its nutritional value and organoleptic quality. An effective production process for enzymatic hydrolysis of duck blood corpuscle was successfully developed and optimized by response surface methodology. Optimal conditions based on achieving a high value of trichloroacetic acid solubility index were substrate concentration of 14 g/100 mL, temperature 51°C, initial pH 7.0, and time 7.5 h. The electrophoretic patterns of the protein hydrolysate were investigated, and a large diffuse band was observed in the vicinity of 5 kDa. The organoleptic quality of spray-dried blood corpuscle hydrolysate was also evaluated, indicating that enzymatic hydrolysis and decoloration methods were feasible and cost-effective to achieve the desirable bright yellow product without bitterness. In vitro protein digestibility of blood corpuscle hydrolysate was 96.32 ± 0.50%, which was better than that of soybean, fish meal, and casein. Based on the amino acid composition and nutritional parameters, we found that the spray-dried blood corpuscle hydrolysate had abundant nutritional value and high potential for application as an ingredient in nonruminant animal feed.

Effect of different processing techniques on nutritional characteristics of oat (Avena sativa) grains and formulated weaning mixes.

One of the variety of oat, UPO 94 was processed by two simple processing techniques. One method is malting and other is roasting. Malted and roasted oat flour as well as weaning mixes prepared from these two processed flour were analyzed for their nutrient composition, alpha amylase activity and in-vitro protein digestibility. For making weaning mix, oat flour, wheat flour, green gram and skim milk powder were taken in a ratio of 30:30:25:15 respectively. Higher moisture, ash, crude fat, energy, amylase activity, and in-vitro protein digestibility were reported in malted oat flour and weaning mix prepared from malted flour. The minerals, calcium (180.0 mg/100 g) and iron (7.9 mg/100 g) were also higher in malted weaning mix as compared to roasted weaning mix. Both malted and roasted weaning gruels were evaluated for sensory quality characteristics and both were found acceptable by the panel members.

Effect of extraction pH on amino acids, nutritional, in-vitro protein digestibility, intermolecular interactions, and functional properties of guar germ proteins.

The chemical compositions, intermolecular interactions, and functional properties of guar germ proteins (GGP) were investigated at different extraction pH (7 to 11). The protein efficiency ratio, essential amino acid index (46.53), predicted biological value (39.02), nutritional index (42.67), and protein purity (91.69 %) were found to be highest at pH 9. The in-vitro protein digestibility of GGP sample was highest at pH 11. From SDS-PAGE, the band intensity (<10 kDa) became thinner with an increase in extraction pH from 7 to 9 and then thicker. Meanwhile, smallest particle size and weaker ionic and hydrogen bonds were found at pH 11. The ß-sheet content was more dominating in GGP samples. Moreover, higher denaturation temperatures of GGP samples indicated that protein molecules had a compact tertiary structure. Furthermore, the GGP extracted at pH 7 showed better functional properties. The principal component analysis suggested that pH 9 was more suitable for isolating GGP.

High-intensity ultrasound treatment of Atlantic cod: Impact on nutrients, structure, sensory quality, bioactivity, and in-vitro digestibility.

This study evaluates the impact of high-intensity ultrasound (HIU) on the physicochemical properties and in-vitro digestibility of Atlantic cod (Gadus morhua). Various ultrasound durations (0-60 min) were applied to assess changes in color attributes, total antioxidant capacity (TAC), total flavonoid content (TFC), total phenolic content (TPC), total protein content, and in-vitro protein digestibility (IVPD). Results indicated HIU maximumly increased TAC, TFC, TPC, and peptide content before digestion by 7.28 % (US60), 3.00 % (US30), 32.43 % (US10), and 18.93 % (US60), respectively. While HIU reduced total protein content, it enhanced IVPD by up to 12.24 % (US30). Color attributes electron microscopy reflected structural changes in the cod samples, suggesting the effectiveness of HIU in altering protein structures. These findings highlight HIU's potential as a non-thermal technique for improving the sensory and nutritional quality of Atlantic cod, offering valuable insights for the seafood processing industry and consumers.

Bioaccessibility and Digestibility of Proteins in Plant-Based Drinks and Cow's Milk: Antioxidant Potential of the Bioaccessible Fraction.

During the last years, a strong increase in the sales volume and consumption of plant-based drinks was observed, which were partly used as an alternative to cow's milk. As milk is a relevant protein source in many countries, we have investigated the protein bioaccessibility and digestibility of soy, almond, and oat drinks in comparison to milk using the tiny-TIMsg gastrointestinal model. The relative protein digestibility of all products was between 81% (soy drink) and 90% (milk). The digestible indispensable amino acid score (DIAAS) in vitro method was used to estimate the protein nutritional quality. The highest DIAAS values were obtained for milk in tryptophan (117%) and soy drink in sulfur containing amino acids (100%). Oat drink was limited in lysine (73%), almond drink in lysine (34%) and the sulfur containing amino acids (56%). Additionally, the antioxidant activity of the bioaccessible fractions was analyzed using Trolox equivalent antioxidative capacity and oxygen radical absorbance capacity assays, revealing a higher antioxidative potential of milk and soy drink compared to oat and almond drink.

Microwave irradiation of guar seed flour: Effect on anti-nutritional factors, phytochemicals, in vitro protein digestibility, thermo-pasting, structural, and functional attributes.

Guar seed flour (GSF) has a high amount of carbohydrates, proteins, phytochemicals, and anti-nutritional factors (ANFs), which limits its use. To address this issue, the current study was undertaken to understand the effect of microwave (MW) irradiation on ANFs, phytochemicals, in vitro protein digestibility (IVPD), and functional attributes of GSF at varying power density (Pd: 1-3 W/g) and duration (3-9 min). The ANFs were determined using a colorimetric assay and a Fourier transform infrared spectrum. At 3 Pd-9 min, the maximum reduction in ANFs (tannin, phytic acid, saponin, and trypsin inhibitor activity) was observed. Higher Pd and treatment duration increased antioxidant activity and total phenolic content, except for total flavonoid content. Furthermore, compared to the control sample (78.38%), the IVPD of the GSF samples increased to 3.28% (3 Pd-9 min). An increase in Pd and duration of MW treatment improved the thermal and pasting properties of GSF samples up to 2 Pd-9 min. Due to inter- and intramolecular hydrogen bonding degradation, the relative crystallinity of the 3 Pd-9 min treated GSF sample was 30.58%, which was lower than that of the control (40.08%). In MW-treated samples, SEM images revealed smaller clusters with rough and porous structures. However, no noticeable color (ΔE) changes were observed in MW-treated samples. Aside from water absorption capacity and water solubility index, MW treatment reduced oil absorption capacity, foaming capacity, and emulsifying capacity. As demonstrated by principal component analysis, MW irradiation with moderate Pd (2-3) was more effective in reducing ANFs, retaining nutritional contents, and improving the digestible properties of GSF, which could be a potential ingredient for developing gluten-free products.

In vitro protein digestibility to replace in vivo digestibility for purposes of nutrient content claim substantiation in North America's context.

The reliance by North American regulatory authorities on in vivo rodent bioassays-Protein Correct-Amino Acid Score (PDCAAS) in the U.S. and Protein Efficiency Ratio (PER) in Canada-to measure the protein quality for protein content claim substantiation represents a major barrier for innovation in the development and marketing of protein foods. Although FAO in 2013 proposed a new method (Digestible Indispensable Amino Acid Score, DIAAS), it is still not used for protein content claim substantiation in any jurisdiction. Together with public health efforts to increase the consumption of plant-based foods, removing hurdles is key to incentivizing the food industry to measure protein digestibility in making food formulation decisions as well as in claiming protein content on product labels. To address this issue, a pathway has been proposed to position alternative methods for in vitro protein digestibility in collaborative studies to generate the data necessary for method approval by a certifying body. The latter is critical to the potential recognition of these methods by both Health Canada and the US FDA. The purpose of this article is to briefly summarize the state-of-the-art in the field, to inform the research community of next steps, and to describe the path engaging collaborative laboratories in a proficiency test as the first step in moving forward toward acceptance of in vitro digestibility methods. Throughout, a consultative and iterative process will be utilized to ensure the program goals are met. Success will be achieved when the proposed path results in the acceptance of an in vitro methods for protein digestibility used for PDCAAS determinations, which will enable increased protein analyses and improved nutrition labeling of protein foods.

Current advances for in vitro protein digestibility.

Protein is an essential macronutrient in our diet, source of nitrogen and essential amino acids, but the biological utilization of dietary protein depends on its digestibility and the absorption of amino acids and peptides in the gastrointestinal tract. The methods to define the amount and the quality of protein to meet human nutritional needs, such as the Digestible Indispensable Amino Acid Score (DIAAS), require the use of animal models or human studies. These in vivo methods are the reference in protein quality evaluation, but they are expensive and long-lasting procedures with significant ethical restrictions. Therefore, the development of rapid, reproducible and in vitro digestion methods validated with in vivo data is an old demand. This review describes the challenges of the in vitro digestion methods in the evaluation of the protein nutritional quality. In addition to the technical difficulties to simulate the complex and adaptable processes of digestion and absorption, these methods are affected by similar limitations as the in vivo procedures, i.e., analytical techniques to accurately determine bioavailable amino acids and the contribution of the endogenous nitrogen. The in vitro methods used for the evaluation of protein digestibility, with special attention on those showing comparative data, are revised, emphasizing their pros and cons. The internationally harmonized digestion protocol proposed by the INFOGEST network is being adapted to evaluate protein and amino acid digestibility. The inter-laboratory reproducibility of this protocol was demonstrated for dairy products. The in vivo/in vitro comparability results obtained to date with this protocol for several plant and animal sources are promising, but it requires an extensive validation with a wider range of foods and substrates with known in vivo digestibility. These in vitro methods will probably not be applicable to all foods, and therefore, it is important to identify their limitations, not to elude their use, but to apply them within the limits, by using the appropriate standards and references, and always as a complementary tool to in vivo tests to reduce their number.

Atmospheric cold plasma induced nutritional & anti-nutritional, molecular modifications and in-vitro protein digestibility of guar seed (Cyamopsis tetragonoloba L.) flour.

The present study was carried out to investigate the effect of atmospheric cold plasma treatment on the nutritional, anti-nutritional, functional, morphological, and digestibility of guar seed (Cyamopsis tetragonoloba L.) flour. Here, guar seed flour was kept inside the plasma reactor for 5 to 20 min at different power levels (10 & 20 kV). The cold plasma treatment (CPT) significantly (p < 0.05) reduced the carbohydrate (46.87 - 36.81 %), protein (27.15 - 25.88 %), and increased the WAC (1.89 - 2.91 g/g), OAC (1.18 - 2.17 g/g), FC (113 - 186.17 %), and pasting properties of guar seed flour. High-intensity plasma-treated samples (20 kV-20 min) contained lesser tannin, phytic acid, and saponin with reduced the nutritional value. The FTIR spectrum suggested that functional group formation or destruction might have occurred in the plasma-treated samples. Additionally, the crystallinity is reduced with increasing applied voltage or duration. The SEM analysis reveals that CPT resulted in the formation of rough surfaces with highly porous structures. On the other hand, CPT significantly reduced the trypsin inhibitor activity and had a minor impact on in-vitro protein digestibility except for the 20 kV-20 min treated sample. In PCA analysis, 10 kV-15 min treated samples exhibited better nutritional value, functional, and pasting properties with maximum impact of anti-nutritional factors. From the results, it can be concluded that treatment duration rather than the applied voltage plays a significant role in preserving the nutritional content.