EVALUATION OF EFFECTS OF SOAKING AND PRECOOKING CONDITIONS ON THE QUALITY OF PRECOOKED DEHYDRATED PEA, LENTIL AND CHICKPEA PRODUCTS

Application of state diagrams to understand the nature and kinetics of (bio)chemical reactions in dry common bean seeds: A scientific guide to establish suitable postharvest storage conditions

Storage is a fundamental part of the common bean postharvest chain that ensures a steady supply of safe and nutritious beans of acceptable cooking quality to the consumers. Although it is known that extrinsic factors of temperature and relative humidity (influencing the bean moisture content) control the cooking quality deterioration of beans during storage, the precise interactions among these extrinsic factors and the physical state of the bean matrix in influencing the rate of quality deteriorative reactions is poorly understood. Understanding the types and kinetics of (bio)chemical reactions that influence the cooking quality of beans during storage is important in establishing suitable storage conditions to ensure quality stability. In this review, we integrate the current insights on glass transition phenomena and its significance in describing the kinetics of (bio)chemical reactions that influence the cooking quality changes during storage of common beans. Furthermore, a storage stability map based on the glass transition temperature of beans as well as kinetics of the main (bio)chemical reactions linked to cooking quality deterioration during storage was designed as a guide for determining appropriate storage conditions to ensure cooking quality stability.

The Impact of Drying and Rehydration on the Structural Properties and Quality Attributes of Pre-Cooked Dried Beans

Fresh common beans can be made ‘instant’ to produce fast-cooking beans by first soaking and cooking the beans before drying to create a shelf-stable product that can be rehydrated at the time of use. This study investigated the interplay between the drying process (air, vacuum and freeze drying), the microstructure and functional attributes of rehydrated pre-cooked beans. The microscopic study revealed that the three different drying techniques resulted in distinctly different microstructures, with the freeze drying process resulting in highly porous materials, while the air- and vacuum-dried samples underwent shrinkage. Additionally, the rehydration behavior (modeled using empirical and diffusion models) demonstrates that the high rehydration rate of freeze-dried beans is due to capillarity, while rehydration, in the case of air- and vacuum-dried beans, is primarily diffusion-controlled. Irrespective of the drying technique, the high rehydration capacity supports little to no structural collapse or damage to the cell walls. The color and texture of the rehydrated beans did not differ greatly from those of freshly cooked beans. The total peak area of the volatiles of rehydrated beans was significantly reduced by the drying process, but volatiles characteristic of the cooked bean aroma were retained. This new understanding is beneficial in tailoring the functional properties of pre-cooked dry convenient beans requiring short preparation times.

Understanding the Relations Among the Storage, Soaking, and Cooking Behavior of Pulses: A Scientific Basis for Innovations in Sustainable Foods for the Future

The world faces challenges that require sustainable solutions: food and nutrition insecurity; replacement of animal-based protein sources; and increasing demand for convenient, nutritious, and health-beneficial foods; as well as functional ingredients. The irrefutable potential of pulses as future sustainable food systems is undermined by the hardening phenomenon that develops upon their storage under adverse conditions of temperature and relative humidity. Occurrence of this phenomenon indicates storage instability. In this review, the application of a material science approach, in particular the glass transition temperature concept, is presented to explain phenomena of storage instability such as the occurrence of hardening and loss of viability under adverse storage conditions. In addition to storage (in)stability, application of this concept during processing of pulses is discussed. The state-of-the-art on how hardening occurs, that is, mechanistic insights, is provided, including a critical evaluation of some of the existing postulations using recent research findings. Moreover, the influence of hardening on the properties and processing of pulses is included. Prevention of hardening and curative actions for pulses affected by the hardening phenomenon are described in addition to the current trends on uses of pulses and pulse-derived products. Based on the knowledge progress presented in this review, suggestions for the future include: first, the need for innovation toward implementation of recommended solutions for the prevention of hardening; second, the optimization of the identified most effective and efficient curative action against hardening; and third, areas to focus on for elucidation of mechanisms of hardening, although existing analytical methods require advancement.

Effect of Dehydration Conditions on the Chemical, Physical, and Rehydration Properties of Instant Whole Bean (Phaseolus vulgarisL. var. Azufrado)

The purpose of this study was to evaluate the effect of dehydration conditions on the chemical, physical, and rehydration properties of instant whole beans (Phaseolus vulgarisL. var. Azufrado) using a 22factorial design (air temperature: 25°C and 30°C, air velocity: 0.5 m/s and 1.0 m/s). To determine the kinetic parameters, the rehydration data were fitted to three models: Peleg’s, First Order, and Sigmoid. The protein, fat, and ash contents of the beans were not significantly affected (P>0.05) by the dehydration conditions. Of the 11 physical properties of the instant whole beans, only water activity and splitting were significantly affected by dehydration conditions (P<0.05), with a range from 0.58 to 0.67 and from 2.90% to 5.87%, respectively. Of the three models tested, the First Order model gave the best fit for rehydration, with no significant differences (P>0.05) between the observed and predicted equilibrium moisture contents of the instant whole beans. Regarding the rehydration kinetics for the instant whole beans, the activation energy values ranged from 23.56 kJ/mol to 30.48 kJ/mol, depending on the dehydration conditions. The dehydration conditions had no significant effect (P>0.05) on the rehydration properties of instant whole beans.