Modelling of the nutritional behaviour of cowpea seeds during soaking, germination and cooking process.

Two modelling approaches previously developed and describing separately the diffusion-reaction of folates and alpha-galactosides during cowpea seed soaking, germination and cooking processes were combined here to simulate the effect of some key processing parameters on the nutritional value of cowpea seeds. The simulator was upgraded, considering thermal-pH dependency of both diffusivities and reactivities of folates and alpha-galactosides together with water-to-seed ratio and starch gelatinization. The simulations showed that soaking and cooking processes were deleterious for folates whereas germination promoted the production of folates while reducing alpha-galactosides concentration. This study suggests that a long germination (96 h), followed by a short cooking seems to be optimal both in terms of nutritional value and degree of cooking.

Modelling Processes and Products in the Cereal Chain.

In recent years, modelling techniques have become more frequently adopted in the field of food processing, especially for cereal-based products, which are among the most consumed foods in the world. Predictive models and simulations make it possible to explore new approaches and optimize proceedings, potentially helping companies reduce costs and limit carbon emissions. Nevertheless, as the different phases of the food processing chain are highly specialized, advances in modelling are often unknown outside of a single domain, and models rarely take into account more than one step. This paper introduces the first high-level overview of modelling techniques employed in different parts of the cereal supply chain, from farming to storage, from drying to milling, from processing to consumption. This review, issued from a networking project including researchers from over 30 different countries, aims at presenting the current state of the art in each domain, showing common trends and synergies, to finally suggest promising future venues for research.

Modelling folates reaction kinetics during cowpea seed germination in comparison with soaking.

Folate is a fundamental vitamin for metabolism in plants and humans. A modelling approach has been developed to characterize the reactivity of folates in cowpea seeds during germination at 30 °C, using a water-to-seed ratio of 1:1 (w/w). For this purpose, the concentrations of folic acid, 10-formylfolic acid, 5-methyltetrahydrofolate, 5-formyltetrahydrofolate and tetrahydrofolate were determined in seeds during germination times up to 96 h. Two reaction models were sequentially built and adjusted to experimental data to describe changes in concentration in cowpea seed during two germination phases: before 14 h and after 48 h. Results showed intense enzymatic interconversion of all folate vitamers into 5-methyltetrahydrofolate before 14 h of germination and high enzymatic production of 5-methyltetrahydrofolate, 5-formyltetrahydrofolate and tetrahydrofolate after 48 h of germination. This study suggests that a long germination process could be more beneficial than soaking to increase the production of bioavailable folates within the seed for human consumption.

Impact of soaking process on the microstructure of cowpea seeds in relation to solid losses and water absorption.

A cytohistological investigation was performed to better understand the structural alterations of cowpea seeds in relation with soaking. Thin sections obtained from seeds soaked at 30 °C, 60 °C and 95 °C were treated to specifically visualize starch, proteins, cellulose and pectin. Micropyle behavior as well as water uptake and dry matter loss were also monitored. A Soaking at 30 °C induced slight alteration of parenchymatous cells of cotyledons, whereas drastic alterations were observed at 60 °C and intense alterations at 95 °C. All these structural modifications of cells could explain losses of nutrients and antinutritional factors at the highest soaking temperature (95 °C). The size of the apertures in the micropyle sections varied depending on both soaking temperature and time. At 30 °C and 60 °C, the micropyle aperture enabled notable water uptake by seeds. At 95 °C, water was entirely taken up through the testa. These results show that models describing nutrients losses and water uptake should account for these structure changes during soaking of legumes.

Kinetic study of enzymatic α-galactoside hydrolysis in cowpea seeds.

The endogenous alpha-galactosidase activity of cowpea seeds was characterized and modelled assuming Michaelian behavior. The aim is to use the resulting knowledge to optimize alpha-galactoside degradation during the soaking-cooking process. In this study, the alpha-galactosidase enzyme from Wankoun cowpea was extracted and its enzymatic activity was analyzed as a function of temperature, pH and the presence of some inhibitors. Enzymatic activity was optimal around 35 °C and a pH of 5.8. Activation and inactivation energy was evaluated at 50 ±â€¯3 and 103 ±â€¯9 kJ.mol-1, respectively. The strongest inhibitor was galactose with an inhibition constant KI of 0.28 ±â€¯0.03 mM. Incubation of the enzyme extract with alpha-galactosides revealed a 10-h lag phase in the early stages that could be due to low pH, the action of inhibitors including galactose and the biosynthesis of alpha-galactosides. After the lag phase, the degradation of each alpha-galactoside occurred without the appearance of any intermediary product. The degradation of alpha-galactosides was observed with a Km of 1.7 ±â€¯0.3 mM for raffinose; 3.6 ±â€¯0.6 mM for stachyose and 15.9 ±â€¯0.1 mM for verbascose. A long soaking step around 35 °C is suggested to maximize the alpha-galactosides enzymatic degradation.

Beyond nutrient-based food indices: a data mining approach to search for a quantitative holistic index reflecting the degree of food processing and including physicochemical properties.

Processing has major impacts on both the structure and composition of food and hence on nutritional value. In particular, high consumption of ultra-processed foods (UPFs) is associated with increased risks of obesity and diabetes. Unfortunately, existing food indices only focus on food nutritional content while failing to consider either food structure or the degree of processing. The objectives of this study were thus to link non-nutrient food characteristics (texture, water activity (aw), glycemic and satiety potentials (FF), and shelf life) to the degree of processing; search for associations between these characteristics with nutritional composition; search for a holistic quantitative technological index; and determine quantitative rules for a food to be defined as UPF using data mining. Among the 280 most widely consumed foods by the elderly in France, 139 solid/semi-solid foods were selected for textural and aw measurements, and classified according to three degrees of processing. Our results showed that minimally-processed foods were less hyperglycemic, more satiating, had better nutrient profile, higher aw, shorter shelf life, lower maximum stress, and higher energy at break than UPFs. Based on 72 food variables, multivariate analyses differentiated foods according to their degree of processing. Then technological indices including food nutritional composition, aw, FF and textural parameters were tested against technological groups. Finally, a LIM score (nutrients to limit) ≥8 per 100 kcal and a number of ingredients/additives >4 are relevant, but not sufficient, rules to define UPFs. We therefore suggest that food health potential should be first defined by its degree of processing.

Multi-response modeling of reaction-diffusion to explain alpha-galactoside behavior during the soaking-cooking process in cowpea.

A modelling approach was developed to better understand the behavior of the flatulence-causing oligosaccharides in cowpea seeds during isothermal water soaking-cooking process. Concentrations of verbascose, stachyose and raffinose were measured both in the seed and in the soaking water during the process (T=30, 60 and 95°C). A reaction-diffusion model was built for the three considered alpha-galactosides both in the seed and in the soaking water, together with a model of water transport in the seed. The model reproduced coupled reaction-diffusion of alpha-galactosides during the soaking-cooking process with a good fit. Produced, diffused and degraded alpha-galactoside fractions were identified by performing a mass balance. During soaking at 30°C, degradation predominated (maximum found for raffinose degradation rate constant of 3.22×10-4s-1) whereas diffusion predominated at higher temperatures (95°C).