Investigating the effects of pre- and post-electron beam treatment on the multiscale structure and physicochemical properties of dry-heated buckwheat starch.

This study presents the effects of dry heat (DH) assisted by pre-and post-electron beam (EB) treatment on buckwheat starch's multiscale structural, physicochemical, and digestive properties. The granule integrity and crystal shape were not affected by the investigated treatments. However, DH and EB treatments decreased amylose content, crystallinity, molecular weight, swelling power, thermal transition temperatures and gelatinization enthalpy while increasing solubility and the content of A chain, B1 chain, and resistant starch. EB application to DH starch promoted subsequent structural changes and enhanced starch properties compared to samples DH-processed alone. In addition, EB-induced starch chain depolymerization and structural rearrangement had sequential effects. EB pre-treatment reduced DH starch's amylose content, molecular weight, and swelling power while enhancing the content of A- chain, rapidly digestible starch, and resistant starch compared with EB post-treatment. This innovative study provides a theoretical basis for the potential applicability of EB irradiation in modifying the properties of DH starch.

Understanding how electron beam irradiation doses and frequencies modify the multiscale structure, physicochemical properties, and in vitro digestibility of potato starch.

To optimize the properties of native potato starch and to broaden its application in the food field, it was treated by electron beam irradiation (EBI) with different irradiation doses (6, 12, and 24 kGy) and frequencies (1, 2, 4, and 8 times), and the effects on the multi-scale structure, physicochemical properties, and in vitro digestibility were investigated. The results indicate that the increased dose aggravates starch degradation, generating more short chains and fragments, and reducing molecular weight, viscosity, and swelling power. Also, the higher dose facilitated the relative crystallinity, enhancing the ΔH and improving the RS content of potato starch. Furthermore, the repeated irradiation exhibited a cumulative dose effect: the short-range order, molecular weight, solubility, and swelling power improved after multiple irradiations. In addition, irradiation doses and frequencies neither destroyed starch's surface nor changed the polarized cross and growth ring. Also, all irradiated starch preserved starch's FT-IR spectrum and crystalline type. Moreover, multiple low-dose irradiations can not only improve the starch properties, but also achieve energy-saving purposes. Thus, as a rapid, green, non-thermal modification technology, EBI can impart low molecular weight, low viscosity and high solubility processing properties to starch, and improve its RS content without destroying the starch granular appearance.

Lutein encapsulated in whey protein and citric acid potato starch ester: Construction and characterization of microcapsules.

The poor water solubility and stability of lutein limit its application in industry. Microencapsulation technology is an excellent strategy to solve these problems. This study used citric acid esterified potato starch and whey protein as an emulsifier to prepare oil-in-water lutein emulsion, and microcapsules were constructed by spray drying technology. The effects of different component proportions on microcapsules' microstructure, physical and chemical properties, and storage stability were analyzed. Citrate esterified potato starch had good emulsifying properties, and when compounded with whey protein, the encapsulation efficiency (EE) of microcapsules increased, and the embedding effect of lutein improved. After microencapsulation, the solubility of lutein increased significantly, reaching over 49.71 %, and gradually raised with more whey protein content. Furthermore, the high proportion of whey protein helped improve microcapsules' EE and thermal properties, with the maximum EE reaching 89.36 %. The glass transition temperatures of microcapsules were all higher than room temperature, which indicated that they keep a stable state under general storage conditions. The experimental results of this study may provide a reference for applying lutein in food and other fields.

Structural, Physicochemical and Functional Properties of Protein Extracted from De-Oiled Field Muskmelon (Cucumis melo L. var. agrestis Naud.) Seed Cake.

For oil plants, the oil extraction method is a crucial factor in influencing the functional characteristics of the protein. However, reports of protein functionality as affected by the oil extraction process are scarce. In this study, field muskmelon seed (FMS) protein was extracted by Soxhlet extraction method (SE), organic solvent extraction method (OSE), aqueous extraction method (AE), and pressing extraction method (PE), and its structure, amino acid profile, physicochemical properties, and functionality were determined. Molecular weight distribution was similar for all FMS proteins, whereas protein aggregates contents were most excellent for SE and OSE. FMS protein comprised predominantly glutamic acid, leucine, aspartic acid, arginine, and proline. Total amino acids content was highest for SE. Differences in functionality between four FMS proteins for different oil extraction methods were vast. PE had the highest value of solubility, and AE exhibited the lowest. AE had the greatest water and oil holding capacity. PE presented better foaming and emulsion capacities than other samples. This study demonstrated that the extraction oil method could impact the protein's physicochemical and associated functional characteristics. High-quality plant oil and protein could be simultaneously obtained by modulating the oil extraction method in future research.

Preparing potato starch nanocrystals assisted by dielectric barrier discharge plasma and its multiscale structure, physicochemical and rheological properties.

Non-thermal plasma has increasingly been used for surface modification of various materials as a novel green technology. In this study, we prepared potato starch nanocrystals (SNCs) assisted by dielectric barrier discharge plasma technology and investigated its multiscale structure, physicochemical properties and rheology. Plasma treatment did not change the morphology and crystalline pattern of SNCs but reduced the crystallinity. The amylose content, swelling power, gelatinization temperature, and apparent viscosity of SNCs decreased after the plasma process by depolymerizing the amylopectin branch chains and degrading SNCs molecules. Besides, plasma increased the rapidly digestible starch and resistant starch content. Changes in rheological properties of plasma treated SNCs suggested that the plasma process increased the flowing capacity. The effective structural and functional changes of plasma treated SNCs confirm that plasma technology has great potential for modification of SNCs.

Pullulanase modification of granular sweet potato starch: Assistant effect of dielectric barrier discharge plasma on multi-scale structure, physicochemical properties.

This study explored the potential application of physical combined enzyme treatment to modify starch granules. Starch was modified by exposure to cold plasma (CP) for 1, 3, and 9 min and to pullulanase (PUL) for 12, 24, and 36 h. Individual treatments with CP and PUL somewhat modified starch structure and physicochemical properties. Nevertheless, compared with native starch and individual treatments, CP-PUL combined treatment significantly (p < 0.05) promoted the subsequent structural modification, increased the short-chain ratio and the amylose content, reduce the molecular weight and the relative crystallinity, and disturb the short-range order. CP also improved the properties of PUL-modified starch, including enhanced solubility, thermal properties and resistance to enzymatic hydrolysis but worsened swelling power and peak viscosity properties. This research provides a new perspective for the rational application of CP-PUL co-treated starch in the food industry.

Application and enantiomeric residue determination of diniconazole in tea and grape and apple by supercritical fluid chromatography coupled with quadrupole-time-of-flight mass spectrometry.

A chiral separation and residue determination method for diniconazole enantiomers in tea, apple, and grape was developed and validated by supercritical fluid chromatography coupled with quadrupole-time-of-flight mass spectrometry (SFC-Q-TOF/MS). The two diniconazole enantiomers were separated on a Chiral CCA column, and the chromatographic conditions (mobile phase proportion and modifier, column temperature, backpressure, and auxiliary solvent) were optimized. The optimal SFC-Q-TOF/MS conditions were selected as a mobile phase of CO2/isopropanol (IPA) (v/v, 96/4), flow rate at 2.0 mL/min, automated back pressure regulator (ABPR) at 2000 psi, column temperature at 25 ℃ and under electrospray ionization positive mode with the best auxiliary solvent of 2 mmol/L ammonium acetate in methanol/water (v/v, 1/1) at 0.20 mL/min flow rate. Residues in tea and fruit samples were extracted by acetonitrile/water (v/v, 4/1 for fruit and 2/1 for tea), purified by Cleanert TPT or Pesti-Carb solid phase extraction column, then analyzed by SFC-Q-TOF/MS with matrix-matched external standard quantification method. The elution order of diniconazole enantiomers on CCA column was R-(-)-diniconazole at first, and S-(+)-diniconazole at second. The standard curve concentration levels of R-(-)-diniconazole and S-(+)-diniconazole in samples ranged from 0.01 mg/L to 1.00 mg/L with the correlation coefficients greater than 0.99. The spiked recoveries of R-(-)-diniconazole and S-(+)-diniconazole in apple and grape at three levels of 0.005, 0.05 and 0.25 mg/kg were in the range of 69.8% to 102.1%, with relative standard deviations (RSDs) (n = 6) between 3.5% and 10.4%, and the limits of quantitation (LOQs) below 0.005 mg/kg. The spiked recoveries in black tea at three levels of 0.01, 0.10, and 0.50 mg/kg were in the range of 85.6% to 90.6%, with the RSDs (n = 6) ranging from 3.9% to 9.5%, and LOQ of 0.01 mg/kg. This residue analysis and determination method for diniconazole enantiomers in apple, grape and tea samples is convenient, reliable, and meets the residue analysis requirement. Also it is applicatied for the residue fates of R-(-)-diniconazole and S-(+)-diniconazole during the fresh tea leaves growing, green tea processing and black tea processing. The degradation half-times (DT50) between R-(-)-diniconazole and S-(+)-diniconazole in the fresh tea leaves growing were 2.9 d and 3.1 d, respectively. The concentrations of R-(-)-diniconazole and S-(+)-diniconazole decreased gradually with time and on the 14th day after application were lower than 10% of the initial concentration. The average enantiomer fractions (EFs) of R-(-)-diniconazole and S-(+)-diniconazole at 2 h, 2, 5, 7, 10 and 14 d after application in fresh tea leaves were 0.505, 0.526, 0.523, 0.558, 0.453 and 0.489, respectively. This result is similar to the result of our last research for the enantiomers of cis-epoxiconazole-another triazole fungicide residues in fresh tea leaves. And in the whole black tea processing, 37.1%-49.3% and 35.9%-57.9% of R-(-)-diniconazole and S-(+)-diniconazole decreased, respectively. The total processing factors (PFs) of R-(-)-diniconazole and S-(+)-diniconazole for the black tea procedure were 0.507-0.629 and 0.421-0.641, respectively. The EFs of R-(-)-diniconazole and S-(+)-diniconazole in black tea processing ranged from 0.432 to 0.532. However, in the whole green tea processing, 22.3%-32.6% and 21.7%-40.3% of R-(-)-diniconazole and S-(+)-diniconazole decreased, respectively. The difference between black tea and green tea is nearly 15%, and in green tea is less decreased than in black tea. The total PFs of R-(-)-diniconazole and S-(+)-diniconazole for the green tea procedure were 0.674-0.777 and 0.597-0.783, respectively. The EFs of R-(-)-diniconazole and S-(+)-diniconazole in green tea processing ranged from 0.473 to 0.504. The PFs illustrated that for R-(-)-diniconazole and S-(+)-diniconazole decrease, the rolling and fermentation were the critical steps in black tea processing, and the rolling was the critical step in green tea processing, respectively.