Cereal Chem. 94(3):524-531The aim of this study was to characterize the physicochemical, functional, and digestion properties of bagasses derived from broad beans, chickpeas, lentils, and white beans, and to isolate the starch and a fiberrich fraction that can be used as a food ingredient. The bagasses showed different chemical compositions that were related to their botanical origin. The further processing that involved mechanical separation of starch yielded up to 69.65% with ³80.12% recovery and high purity (³94.42%), and a fiber-rich fraction (total dietary fiber content ³72.75%) in which the majority was insoluble fiber. The starch digestion fractions of the isolated lentil starch showed the highest amount of slowly digestible starch (30.76%), whereas the white bean contained the highest resistant starch content (15.65%). All starches showed predicted glycemic indexes £ 66.90, which classify them as medium glycemic foods. In vitro protein digestion was higher for the bagasse fraction (up to 89.78%), followed by the fiber-rich fraction (84.36%). This research demonstrates that it is possible to revalorize the use of pulses bagasse, which could contribute to enhance the technological and economic output of the protein isolation process, rendering two potentially functional fractions. † Corresponding

Summary An alkaline solubilisation and isoelectric point precipitation process were used to isolate proteins from broad bean, chickpea, lentil and white bean. The physicochemical, water solubility and foaming properties as well as their protein digestion characteristics of whole flours and its protein extracts were correlated with their molecular characteristics, analysed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR). The processing of pulses resulted in protein recoveries ≥50.12% and yields up to 30.26% for broad bean. The purity of the protein was from 68.27% to 86.58% for chickpea and broad bean, with in vitro digestion values ≥80.59%. The protein extracts showed up to 0.85 mg g−1 of phenolic compounds (gallic acid eq./100 g). The ATR‐FTIR analysis of the extracts showed different proportions of α‐helix and β‐sheet secondary structures of the amide II group. The analysis of the amide III group reflected inter‐ and intramolecular associations that could have influenced their emulsion and foam characteristics.

Previous studies have related the slow digestion properties of isolated starches with their amylose to amylopectin ratio as well as their molecular structure, and in the case of flours, with their accompanying components such as proteins and fibers; which are known to restrict, to different extents the starch digestion by amylolytic enzymes. However, the botanical origin as well as the internal architecture of native starch granules plays a significant role in these characteristics. Moreover, these features can be improved by using hydrothermal treatments, such as heat moisture treatment (HMT) and annealing (ANN), that promote changes to granular architecture, increase internal crystallite order and decrease the amount of amorphous zones. In this study, HMT and ANN treated starches from two bean varieties and a normal maize starch are analyzed in terms of thermal stability, assessed by differential scanning calorimetry, viscosity by rapid visco analysis and in vitro amylolysis. The HMT and ANN treatments promote lower hydrolysis when compared to native granules, due to new and/or improved molecular interactions between starch molecules, assessed by attenuated total reflectance‐fourier transform infra red spectroscopy; such interactions increase the amount of crystalline residues after digestion, which is related with lower water absorption during cooking, and enhanced thermal stability, despite the lower enthalpies in thermal treated starches (≈3 J g−1 in Black bean with HMT). Furthermore, the hydrolysis residues after 120 min of amylolysis present a higher ratio of crystalline regions, that improve with thermal treatments, this demonstrates that these processes increase the order of existing crystallites due to new molecular interactions among starch molecules.

Whole chickpea flours were subjected to a pilot plant process aimed to understand the effects of jet-cooking followed by a-amylase or isoamylase hydrolyses in terms of physicochemical and the in vitro digestion performance of starch and proteins. Jet-cooked flours generated lower viscosities and had lower gelatinisation temperatures when compared with their raw counterparts; furthermore, the amylolytic enzymes improved both starch and protein in vitro digestion rates (HI of 85.33 and relative digestion of 88.92%, respectively) that were strongly correlated with the amylose content (P < 0.05). By means of principal component analyses (PCA) is concluded that the changes in granular architecture, reflected by lower DH values and new linear structures after isoamylase hydrolysis (treated = 44.36% vs. raw = 26.43%) as well as protein denaturation promoted similar glycemic responses in raw flours compared with jet-cooked counterparts (83.12 and 84.77, respectively). The combination of a thermal-enzymatic method could be a useful alternative to produce novel pulse flours.