Pinhão starch was modified by annealing (ANN), heat-moisture (HMT) or sonication (SNT) treatments. The starch was also modified by a combination of these treatments (ANN-HMT, ANN-SNT, HMT-ANN, HMT-SNT, SNT-ANN, SNT-HMT). Whole starch and debranched starch fractions were analyzed by gel-permeation chromatography. Moreover, crystallinity, morphology, swelling power, solubility, pasting and gelatinization characteristics were evaluated. Native and single ANN and SNT-treated starches exhibited a CA-type crystalline structure while other modified starches showed an A-type structure. The relative crystallinity increased in ANN-treated starches and decreased in single HMT- and SNT-treated starches. The ANN, HMT and SNT did not provide visible cracks, notches or grooves to pinhão starch granule. SNT applied as second treatment was able to increase the peak viscosity of single ANN- and HMT-treated starches. HMT used alone or in dual modifications promoted the strongest effect on gelatinization temperatures and enthalpy.

Starch and cellulose fibers were isolated from grains and the husk from barley, respectively. Biodegradable films of native starch or oxidized starches and glycerol with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. Cellulose fibers isolated from the barley husk were obtained with 75% purity and high crystallinity. The morphology of the films of the oxidized starches, regardless of the fiber addition, was more homogeneous as compared to the film of the native starch. The addition of cellulose fibers in the films increased the tensile strength and decreased elongation. The water vapor permeability of the film of oxidized starch with 20% of cellulose fibers was lower than the without fibers. However the films with cellulose fibers had the highest decomposition with the initial temperature and thermal stability. The oxidized starch and cellulose fibers from barley have a good potential for use in packaging. The addition of cellulose fibers in starch films can contribute to the development of films more resistant that can be applied in food systems to maintain its integrity.

Carioca bean starch is isolated and modified by annealing (ANN), heat‐moisture‐treatment (HMT), and sonication (SNT), as well as combined dual modifications (ANN‐HMT, ANN‐SNT, HMT‐ANN, HMT‐SNT, SNT‐ANN, SNT‐HMT). Single and dual modifications did not cause molecular damage in starch fractions. Starch B‐type fraction in native Carioca bean increases after the ANN treatment. Dual ANN‐SNT modification (ANN‐SNT or SNT‐ANN) promotes a synergic behavior on crystallite collapse, causing a decrease in relative crystallinity. The ANN as the second treatment results in irregular surface morphologies and granule disintegration. The ANN‐SNT and SNT‐ANN modifications increase the pasting viscosity synergistically in contrast to individual SNT or ANN treatments. The HMT process promotes the disruption of crystallites upon the subsequent ANN treatment, confirmed by an increase in enthalpy (ΔH). The starch modification techniques reported here can provide new opportunities to utilize damaged and hard‐to‐cook Carioca beans in the food industry.

No abstract

Starch nanocrystals (SNCs) are insoluble platelet particles with multifunctional properties. SNCs production is mainly based on acid hydrolysis of cornstarch with low yield. This study focuses on investigating the effect of pretreatments (heat‐moisture‐treatment [HMT], annealing [ANN], and sonication [SNT]) on unconventional pinhão starch to produce SNCs by acid hydrolysis to improve the yield and SNCs properties. All starches hydrolysis is described by a first‐order model reaction and shown two phases related at k values. The faster hydrolysis is from SNT (k = 0.61 day−1) and the slower one is at ANN (k = 0.40 day−1). Furthermore, the acid hydrolysis is described by a rapid (0–2 days) phase, followed by a slow phase lasing 3–7 days. The HMT increases the yield of the SNCs (14.7%) but promotes losses in the RC (47.34%) as compared with the native starch (yield 10.23%; RC 52.23%). The ANN improves crystallites perfection, protecting them from acid attack. The pretreatments allow pinhão starch to be used as promising feedstock to produce SNCs with good yield and RC. In addition, ANN can be useful to improve the thermal stability and SNT to speeding up the hydrolysis for SNCs production, while HMT can increase the hydrolysis yield.