Dielectric barrier discharge cold plasma modifies the multiscale structure and functional properties of banana starch.

Banana starch has attracted significant attention due to its abundant content of resistant starch. This study aims to compare the multiscale structure and functional properties of banana starch obtained from five cultivated varieties and investigate the impact of dielectric barrier discharge cold plasma (DBD) treatment on these starch characteristics. All five types of natural banana starch exhibited an elliptical and irregular shape, conforming to the CB crystal structure, with a bimodal distribution of branch chain lengths. The resistant starch content ranged from 88.9 % to 94.1 %. Variations in the amylose content, amylopectin branch chain length distribution, and structural characteristics resulted in differences in properties such as gelatinization behavior and sensitivity to DBD treatment. The DBD treatment inflicted surface damage on starch granules, reduced the amylose content, shortened the amylopectin branch chain length, and changed the relative crystallinity to varying degrees. The DBD treatment significantly increased starch solubility and light transmittance. Simultaneously, it resulted in a noteworthy decrease in peak viscosity and gelatinization enthalpy of starch paste. The in vitro digestibility test showed that 76.2 %-86.5 % of resistant starch was retained after DBD treatment. The DBD treatment renders banana starch with reduced viscosity, increased paste transparency, enhanced solubility, and broadens its potential application.

Extraction of Pectin from Passion Fruit Peel: Composition, Structural Characterization and Emulsion Stability.

Extraction methods directly affect pectin extraction yield and physicochemical and structural characteristics. The effects of acid extraction (AE), ultrasonic-assisted acid extraction (UA), steam explosion pretreatment combined with acid extraction (SEA) and ultrasonic-assisted SEA (USEA) on the yield, structure, and properties of passion fruit pectin were studied. The pectin yield of UA was 6.5%, equivalent to that of AE at 60 min (5.3%), but the emulsion stability of UA pectin was poor. The pectin obtained by USEA improved emulsion stability. Compared with UA, it had higher protein content (0.62%), rhamnogalacturonan I (18.44%) and lower molecular weight (0.72 × 105 Da). In addition, SEA and USEA had high pectin extraction yields (9.9% and 10.7%) and the pectin obtained from them had lower degrees of esterification (59.3% and 68.5%), but poor thermal stability. The results showed that ultrasonic-assisted steam explosion pretreatment combined with acid extraction is a high-efficiency and high-yield method. This method obtains pectin with good emulsifying stability from passion fruit peel.