Effect of refrigerated storage on probiotic viability and the production and stability of antimutagenic and antioxidant peptides in yogurt supplemented with pineapple peel

Abstract

Fruit by-products are good resources of carbohydrates, proteins, vitamins, and minerals, which may function as growth nutrients for probiotic bacteria. This research aimed at evaluating effects of pineapple peel powder addition on the viability and activity of Lactobacillus acidophilus (ATCC 4356), Lactobacillus casei (ATCC393), and Lactobacillus paracasei ssp. paracasei (ATCC BAA52) in yogurts throughout storage at 4°C for 28d. Plain and probiotic yogurts supplemented with or without pineapple peel powder or inulin were prepared. The probiotic counts in supplemented yogurts at 28d of storage ranged from 7.68 and 8.03 log cfu/g, one log cycle higher compared with nonsupplemented control yogurt. Degree of proteolysis in synbiotic yogurts was significantly higher than plain yogurts and increased substantially during storage. Crude water-soluble peptide extract of the probiotic yogurt with peel possessed stronger antimutagenic and antioxidant activities [evaluated measuring reducing power and scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl; 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid), and hydroxyl radicals] than control and maintained during storage. Pineapple peel, a by-product of juice production, could be proposed as a prebiotic ingredient in the manufacture of yogurts with enhanced nutrition, and functionality.

Physicochemical, textural and rheological properties of probiotic yogurt fortified with fibre-rich pineapple peel powder during refrigerated storage

“…Whole pineapples [Ananas comosus (L.) Merrill] were purchased from a local supermarket (Woolworths Limited, Werribee, Australia) and utilized for preparation of pineapple peel powder (PPP) according to (Sah et al, 2015b). Briefly, crushed peel was immersed for 30 min in hot water (90 C) to inactivate proteolytic enzymes and potential pathogens, freeze-dried, and ground to fine powder.…”

“…In general, firmness significantly increased during cold storage. Specifically, PPP incorporation resulted in lower firmness of yogurt, reflecting weak gel attributable to incompatibility between milk proteins and polysaccharides of PPP (Corredig, Sharafbafi, & Kristo, 2011;Grinberg & Tolstoguzov, 1997), and likely enhanced proteolytic activities of probiotic strains owing to PPP supplementation (Sah et al, 2015b).…”

“…Several studies reported pineapple peel powder (PPP) as a good source of dietary fibre, protein, and minerals, capable of accelerating growth and/or activity of the tested Lactobacilli (Diaz-Vela, Totosaus, Cruz-Guerrero, & De Lourdes P erez-Chabela, 2013;Sah, Vasiljevic, McKechnie, & Donkor, 2015b). A further study reported the utilization of pineapple segments containing immobilized Lactococcus lactis in prepared yogurt to enhance the probiotic viability during 28 days storage (Phuapaiboon, Leenanon, & Levin, 2013).…”

Effect of the addition of roselle (Hibiscus sabdariffa L.) extracts on the rheological, textural, and antioxidant activity of fermented milks

“…For instance, the donation of hydrogen ions involves interrupting free‐radical chain reactions, which is the basis for the assessment of reducing power. The reaction mechanisms mainly involve a hydrogen atom transfer, for DPPH, and both a hydrogen atom transfer and a single electron transfer, for ABTS . ABTS is another synthetic free radical.…”

“…The reaction mechanisms mainly involve a hydrogen atom transfer, for DPPH, and both a hydrogen atom transfer and a single electron transfer, for ABTS. 44 ABTS is another synthetic free radical. It is more versatile than DPPH because the ABTS model can evaluate the scavenging activity in polar as well as non-polar samples, and has the advantage of being soluble in water and organic solvent at a wide range of pH values, with a lower reaction time than that of DPPH method.…”