Starch characterizations of two kinds of seedless Artocarpus altilis (Parkinson) Fosberg originated from China

Comparison of the fine structure and physicochemical properties of proso millet (Panicum miliaceum L.) starch from different ecological regions

Field experiments were conducted to evaluate the morphology, granule size, fine structure, thermal properties, and pasting properties of starch from a waxy (139) and a non-waxy (297) varieties of proso millet grown in Yulin (YY) and Yangling (YL). Compared with the starches from the two varieties grown in YY, the starches from the two varieties grown in YL exhibited higher relative crystallinities, 1045/1022 cm-1 ratio, and amounts of amylopectin long branch chains (APL) but lower 1022/995 cm -1 ratio, amounts of amylopectin short branch chains (APs), and APs/APL ratios. Starches from YL also synthesized long branch-chain amylopectin to enhance intermolecular interactions and form a stable granular structure, which resulted in increased starch gelatinization temperature, enhanced shear resistance, and reduced setback viscosity. Starch from the waxy (139) variety has good application prospects in the food industry because of its high gelatinization temperature and light transmittance and low setback value, which can be ascribed to its extremely low amylose content, polydispersity index, high molecular weight, and dispersed molecular density. It may serve as a reference for applying proso millet starches in the food industry and developing breeding programs to improve starch quality.

Study of unripe and inferior banana flours pre-gelatinized by four different physical methods

This study aimed to prepare the pre-gelatinized banana flours and compare the effects of four physical treatment methods (autoclaving, microwave, ultrasound, and heat-moisture) on the digestive and structural characteristics of unripe and inferior banana flours. After the four physical treatments, the resistant starch (RS) content values of unripe and inferior banana flours were decreased from 96.85% (RS2) to 28.99-48.37% (RS2 + RS3), while C∞ and k values were increased from 5.90% and 0.039 min^-1 to 56.22-74.58% and 0.040-0.059 min^-1, respectively. The gelatinization enthalpy (ΔHg) and I_1047/1022 ratio (short-range ordered crystalline structures) were decreased from 15.19 J/g and 1.0139 to 12.01-13.72 J/g, 0.9275-0.9811, respectively. The relative crystallinity decreased from 36.25% to 21.69-26.30%, and the XRD patterns of ultrasound (UT) and heat-moisture (HMT) treatment flours maintained the C-type, but those samples pre-gelatinized by autoclave (AT) and microwave (MT) treatment were changed to C + V-type, and heat-moisture (HMT) treatment was changed to A-type. The surface of pre-gelatinized samples was rough, and MT and HMT showed large amorphous holes. The above changes in structure further confirmed the results of digestibility. According to the experimental results, UT was more suitable for processing unripe and inferior banana flours as UT had a higher RS content and thermal gelatinization temperatures, a lower degree and rate of hydrolysis, and a more crystalline structure. The study can provide a theoretical basis for developing and utilizing unripe and inferior banana flours.

Effect of the Amylose Nanoscale Polymerization Index on the Digestion Kinetics and Mechanism of Recombinant Chinese Seedless Breadfruit Starch Triadic Complexes

The demand for multicomponent foods to meet human energy and nutritional needs has been increasing; however, few studies have addressed the theoretical basis for their preparation. We investigated the effect of the nanoscale polymerization index (DPw) of amylose on the logarithm of slope plot-based kinetics and the mechanism of digestion of starch-lauric acid-β-lactoglobulin protein complexes. Amylose from each of the five Chinese seedless breadfruit species was mixed with breadfruit amylopectin with the highest resistant starch (RS) content to form starch ternary complexes with various amylose DPws. All five complexes exhibited V-type crystalline diffraction and rod-like molecular configuration. Characteristic X-ray diffraction peaks and Fourier transform-infrared spectra of the ternary complexes revealed similar molecular configurations. As the amylose DPw increased, the complexing index, relative crystallinity, short-range order, weight-average molar mass, molecular density index, gelatinization temperature, decomposition temperature, RS, slowly digestible starch (SDS), and speed rate constants at the second hydrolysis stage (k₂) increased, whereas the semicrystalline lamellae thickness, mass fractal structure parameter, average characteristic crystallite unit length, radius of gyration, fractal dimension and cavities of granule surface microstructure, final viscosity, interval speed rate from SDS to RS, equilibrium concentration, and glycemic index decreased. The digestion kinetics exhibited highly significant variation according to the physiochemical properties and multiscale supramolecular structure (r > 0.99 or r < -0.99, p < 0.01). Together, these results identify amylose DPw as an important structural factor that markedly affects the kinetics and mechanism of ternary complex digestion and provide a new theoretical direction for the production of starch-based multicomponent foods.