Improved konjac glucomannan/curdlan-based emulsion coating by mung bean protein addition for cherry tomato preservation

Biopolymer-based emulsion systems have been used for food preservation. In this study, mung bean protein (MBP) was added to konjac glucomannan (KGM)/curdlan-based camellia oil emulsion (KC-CO) to develop KCM-CO emulsion system. KCM-CO emulsions showed good compatibility and stability during storage. The confocal laser scanning microscopy, atomic force microscope, and infrared spectroscopy revealed that camellia oil was successfully emulsified by MBP, and the resulting droplets were evenly distributed in the polysaccharide network formed by KGM and curdlan micelles based on hydrogen bonds. The emulsions behaved as an elastic solid, and the KCM-CO emulsion films exhibited a compact microstructure, and the emulsification of MBP enhanced the compatibility, as K₅₄C₄₀M₆-CO had the smoothest surface. The addition of MBP significantly improved the elongation at break (EAB), water contact angle (WCA), dissolution, and gas permeability of the emulsion films. K₅₄C₄₀M₆-CO showed the largest EAB (37.6 %), strong hydrophobicity (WCA = 97.8°), and low water vapor and oxygen permeability. In the preservation experiments, K₅₄C₄₀M₆-CO coating significantly delayed the weight loss (by 41.2 %) and firmness decline (by 54.5 %), and maintained the appearance, total solids, total acids, and ascorbic acid content of cherry tomatoes, and inhibited the respiratory intensity by 44.2 %. This coating showed great potential for fruit and vegetable preservation.