Incorporation of phenolic extracts from different by-products in yoghurts to create fortified and sustainable foods

This work aimed to study and compare the effect of the incorporation of agro-industrial by-products (chestnut shell, grapeseed, and pomegranate peel) into yoghurts to fortify them while assessing their potential to replace synthetic preservatives. From each by-product, phenolic extracts were obtained and characterized. All extracts demonstrated antioxidant and antibacterial properties, and the capacity to inhibit alpha-amylase. Chestnut shell extract stood out regarding antioxidant capacity, displaying values of 1128 and 972 mg(Trolox center dot)g(extract)(-1) , for the assays with DPPH and ABTS, respectively. Ten yoghurts were produced (negative control, positive control with 0.1% of sorbic acid, two for each extract with 0.1% and 0.2% of extract, a mixture of extracts and a mixture of extracts with sorbic acid), and stored at 4 degrees C. The incorporation of the extracts into the yoghurts maintained their physical-chemical properties and microbiological safety. The samples inhibited the growth of Escherichia coli and Staphylococcus aureus. Oxidative analysis proved that higher concentrations of extract had similar results to synthetic antioxidants. The results showed the viability to fortify yoghurts with the incorporation of by-product extracts, developing a value-added food. Furthermore, revealed the possibility of these extracts replacing syn-thetic preservatives and antioxidants.

Automated summary

The aim of this study was to investigate the effects of incorporating agro-industrial by-products into yoghurt as fortifiers and potentially replacing synthetic preservatives. Phenolic extracts were obtained and characterized from each by-product, showing antioxidant and antibacterial properties, as well as the ability to inhibit alpha-amylase. The yoghurts with incorporated extracts maintained their physical-chemical properties and microbiological safety, inhibited the growth of Escherichia coli and Staphylococcus aureus, and exhibited similar oxidative results to synthetic antioxidants, indicating the viability of fortifying yoghurts with by-product extracts.