Impact of soybean protein isolate-chitosan edible coating on the softening of apricot fruit during storage

A soybean protein isolate (SPI)-chitosan edible coating was used to prolong the shelf life of apricots stored at 2 °C. Apricots were coated with two different coating formulations (SPI and SPI combined with chitosan). The changes to several parameters including weight loss, firmness, titratable acidity, soluble solids content, pectin contents, and the nanostructural properties of pectin were investigated to evaluate the effectiveness of the coatings. The coatings, especially the SPI-chitosan coating, significantly decreased the weight loss of apricots. Meanwhile, this treatment prevented the decrease in firmness and benefited the textural properties of the tissue. The atomic force microscopy (AFM) results showed a greater Fq (the percent of pectin chains of particular width or length among all the chains observed by AFM) for the width and length of pectin molecules in the SPI-chitosan coated samples (width ≥ 61 nm; length ≥ 3 μm), which indicated that the SPI-chitosan coating could inhibit pectin degradation. The results showed that the SPI-chitosan coating is an effective method to preserve the quality of apricots.