Utilizing Hydrothermal Processing to Align Structure and In Vitro Digestion Kinetics between Three Different Pulse Types

Processing results in the transformation of pulses’ structural architecture. Consequently, digestion is anticipated to emerge from the combined effect of intrinsic (matrix-dependent) and extrinsic (processed-induced) factors. In this work, we aimed to investigate the interrelated effect of intrinsic and extrinsic factors on pulses’ structural architecture and resulting digestive consequences. Three commercially relevant pulses (chickpea, pea, black bean) were selected based on reported differences in macronutrient and cell wall composition. Starch and protein digestion kinetics of hydrothermally processed whole pulses were assessed along with microstructural and physicochemical characteristics and compared to the digestion behavior of individual cotyledon cells isolated thereof. Despite different rates of hardness decay upon hydrothermal processing, the pulses reached similar residual hardness values (40 N). Aligning the pulses at the level of this macrostructural property translated into similar microstructural characteristics after mechanical disintegration (isolated cotyledon cells) with comparable yields of cotyledon cells for all pulses (41–62%). We observed that processing to equivalent microstructural properties resulted in similar starch and protein digestion kinetics, regardless of the pulse type and (prolonged) processing times. This demonstrated the capacity of (residual) hardness as a food structuring parameter in pulses. Furthermore, we illustrated that the digestive behavior of isolated cotyledon cells was representative of the digestion behavior of corresponding whole pulses, opening up perspectives for the incorporation of complete hydrothermally processed pulses as food ingredients.

Compositional, Structural, and Kinetic Aspects of Lipid Digestion and Bioavailability: In Vitro, In Vivo, and Modeling Approaches

Lipid digestion and bioavailability are usually investigated separately, using different approaches (in vitro, modeling, in vivo). However, a few inclusive studies show that their kinetics are closely linked. Lipid bioavailability kinetics is likely involved in the development and evolution of several diseases, so lipid digestion kinetics could be involved as well and can be modulated by food design or combination. To illustrate this possibility, the compositional and structural aspects of lipid digestion kinetics, as investigated using in vitro and modeling approaches, are presented first. Then, in vivo and mixed approaches enabling the study of both kinetics are reviewed and discussed. Finally, disparate modeling approaches are introduced, and a unifying modeling scheme is proposed, opening new perspectives for understanding the role and interactions of various factors (chemical, physical, and biological) involved in lipid metabolism. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Nutritional and Logarithmic Fungal Count of Brewers’ Grain Under Different Conservation Techniques and Brewery Sources

This study was contained two trials. The objectives of the first and the second trials were to explore variations in nutritional merits and investigate the effect of local conservation practices on nutritional and fungal load dynamics of wet brewers’ grain (WBG) received from different brewery sources, respectively. Fresh WBG samples for the first trial were obtained from four breweries (Meta Abo, Habesha, Dashen and Bedele) located in different districts of the country. Brewers’ grain sample received from Meta Abo brewery factory had superiorly higher (p<0.05) acid detergent fiber, lignin and digestible organic matter in the dry matter (DOMD), but comparable dry matter (DM), total ash, crude protein (CP) and neutral detergent fiber with the other breweries. In the second trial, an attempt was made to evaluate three locally available WBG conservation practices, preservation of WBG using an ensiling technique maintained feed quality slightly comparable to the control sample (freeze dried ) but outperformed (p<0.05) other locally available conservational practices “soaking” and “sun drying “ with minimal loss on feed DM and other nutrients, lower total fungal, yeast and mold colony counts and above all superior CP digestion kinetics as measured through nylon bag degradability constants. If supply is not a constraint under local conditions, ensiling can fairly be recommended as a best bet WBG conservation practice for use at wider scale.

Effect of Yeast-Fermented Citrus Pulp as a Protein Source on Nutrient Intake, Digestibility, Nitrogen Balance and In Situ Digestion Kinetics in Nili Ravi Buffalo Bulls

A study was carried out to evaluate the effect of single cell protein (SCP) supplement as a protein source on nutrient intake, digestibility, nitrogen balance and in situ digestion kinetics in four Nili Ravi buffalo bulls. Four iso-caloric and iso-nitrogenous concentrates containing 3, 6, 9 and 12% of Saccharomyces cerevisiae-fermented citrus pulp were formulated. All animals were fed a ration with a concentrate/forage ratio of 50:50. Diets were provided ad libitum twice a day as a total mixed ration in a 4 × 4 Latin Square Design. Each experimental period lasted 3 weeks while the overall study 12 weeks. The first 2 weeks of each experimental period were used as adaptation period while the third week as collection period. Chemical composition of fermented citrus pulp appeared as an excellent source of protein. No significant difference was observed on dry matter intake, digestibility of nutrients and SCP among all the treatments. Moreover, no significant effect was observed on ruminal pH and ammonia nitrogen at different times. Rate of disappearance and lag time of in situ dry matter digestion kinetics remained nonsignificant regardless of SCP percentage. Based on results of similar nutrients intake, nutrient digestibility, and ruminal parameters it is concluded that SCP could be used in the concentrate diet of ruminant up to 12%. Furthermore, the SCP has the potential of an alternative protein source in animal diet formulation.

Development of a static in vitro digestion model for determination of glycemic index

While in vivo methods have been used to determine the glycemic response of food, they are time consuming, costly, and not suitable for large-scale applications. As an alternative, in vitro digestion models offer fast, reproducible results to study food digestion kinetics that are less expensive than conducting human trials. While there are several in vitro glycemic index (GI) methods used to determine the GI of food, most do not employ methods of in vivo testing. Therefore, we used a static in vitro digestive system, the Dedicated Ryerson University In-vitro Digester (DRUID), that simulates both gastric and intestinal conditions to determine the glycemic response of commonly consumed carbohydrate-containing foods. Samples were collected at regular intervals over a 2h residence time after digestion in the intestinal phase of the DRUID. The DRUID-determined GI values were compared to published in vivo GI values. A Bland-Altman plot showed that there was agreement between the GI values determined from the DRUID compared with published in vivo GI values. In conclusion, the in vitro DRUID can reliably and reproducibly determine the GI across a spectrum of carbohydrate-containing foods, and has the potential to predict the digestion kinetics of novel food products in vivo that may promote human health.

Development of a static in vitro digestion model for determination of glycemic index

While in vivo methods have been used to determine the glycemic response of food, they are time consuming, costly, and not suitable for large-scale applications. As an alternative, in vitro digestion models offer fast, reproducible results to study food digestion kinetics that are less expensive than conducting human trials. While there are several in vitro glycemic index (GI) methods used to determine the GI of food, most do not employ methods of in vivo testing. Therefore, we used a static in vitro digestive system, the Dedicated Ryerson University In-vitro Digester (DRUID), that simulates both gastric and intestinal conditions to determine the glycemic response of commonly consumed carbohydrate-containing foods. Samples were collected at regular intervals over a 2h residence time after digestion in the intestinal phase of the DRUID. The DRUID-determined GI values were compared to published in vivo GI values. A Bland-Altman plot showed that there was agreement between the GI values determined from the DRUID compared with published in vivo GI values. In conclusion, the in vitro DRUID can reliably and reproducibly determine the GI across a spectrum of carbohydrate-containing foods, and has the potential to predict the digestion kinetics of novel food products in vivo that may promote human health.

Exogenous enzymes and probiotics alter digestion kinetics, volatile fatty acid content and microbial interactions in the gut of Nile tilapia

Sustainable aquafeed production requires fishmeal replacement, leading to an increasing use of plant-derived ingredients. As a consequence, higher levels of antinutritional substances, such as non-starch polysaccharides and phytate, are present in aquafeeds, with negative effects on fish performance, nutrient digestibility and overall gut health. To alleviate these negative effects, providing exogenous digestive enzymes and/or probiotics can be an effective solution. In this study, we tested the effect of dietary supplementation of enzymes (phytase and xylanase) and probiotics (three strains of Bacillus amyloliquefaciens) on nutrient digestion kinetics and volatile fatty acid content along the gut, and the distal gut microbiome diversity in Nile tilapia. Chyme volatile fatty content was increased with probiotic supplementation in the proximal gut, while lactate content, measured for the first time in vivo in fish, decreased with enzymes along the gut. Enzyme supplementation enhanced crude protein, Ca and P digestibility in proximal and middle gut. Enzymes and probiotics supplementation enhanced microbial interactions as shown by network analysis, while increased the abundance of lactic acid bacteria and Bacillus species. Such results suggest that supplementation with exogenous enzymes and probiotics increases nutrient availability, while at the same time benefits gut health and contributes to a more stable microbiome environment.