Orange peel fermentation using Lactiplantibacillus plantarum: microbiological analysis and physico-chemical characterisation

Abstract

To find an innovative use for orange peels discarded in the orange juice-making process, a fermentative process was assessed using a Lactiplantibacillus plantarum strain. Blanched or rinsed peels were submerged in a 5% NaCl–3% inoculated sucrose brine for 10 days. Total soluble solids, pH, sugars and total aerobic and anaerobic counts were determined in the brines to characterise the process. The final products were characterised by instrumental texture, colour and volatile composition. The blanching pretreatment had a significant effect on the whole process and the final product characteristics. Anaerobic bacteria total counts were significantly higher in the blanched samples during the whole fermentation, and pH decreased significantly slower in these samples than in the rinsed ones. Rinsed samples were characterised by higher aerobic total counts, higher sucrose consumption and higher glucose, fructose and polyalcohols production. The texture was softer in the pretreated samples, probably due to the blanching process rather than the fermentation. The volatile composition was quite similar between samples, although it was different from one of the raw orange peels due to a significant decrease in various volatile compounds.