Incorporation of fat-soluble bioactive compounds during development processing of a fermented-maize yogurt- like food containing phytosterols and papaya extracts

DESCALZO, ADRIANA; PEREZ CAROLINA; BOUZAS ALDANA; DHUIQUE-MAYER, CLAUDIE

Barcelona

Congreso; The food factor 1 Barcelona conference: Established, emerging and exploratory food science and technology. 1, Barcelone, Espagne, 2 Novembre 2016/4 Novembre 2016.; 2016

Universidad de Barcelona

The aim of this work was to design a functional yogurt-like food obtained from fermented maize, and to study the behaviour of stability and quality parameters during three unit operations: pasteurisation, fermentation and cooking. The products were made with maize grains, wet-milled and sieved (350- mesh). The starch containing liquid was added with skim milk and sugar (C: control and K: kefir treatments), dispersible phytosterols and papaya fresh puree concentrated (DPC) or lyophilized (DPL).Pasteurisation was performed at 65 °C for 20 min. Starters from commercial preparation (Kefir or Lactobacillus bulgaris and Streptococcus thermophillus, Lactina ®, Bulgary) were added in a proportion of 1.2/5 sample (K, ),) at a proportion of 5.6 x 106 CFU/g to C, DPL and DPC treatments. Fermentation was performed in batch system at 37 °C for 16 hrs. Cooking: preparations were cooked at 90 °C under continuous stirring for10 min. The final product was stored at 4 °C in the darkness.pH progressed differently between treatments after fermentation, being lower in C than K and DPC/L treatments (3.81 vs 3.99, P < 0.05) and augmented slightly after cooking (around 4). Oxidation increased after cooking (TBARS), being 2 -fold higher in the DPC/L treatments than in the controls. Total tocopherols were about 3.7- fold higher in the DPC/L products than in the controls, and they were not affected by processing. The addition of papaya augmented the levels of the -tocopherol isomer, whereas the -isomer was the most important in C and K samples.Minor carotenoids, lutein and zeaxanthin, were higher in DPC/L products than in the controls (P < 0.05) and were also not affected by processing. Instead, fermentation favored the release of biologically active lycopene, - carotene and -cryptoxanthin in DPC/L samples, probably due to the effect of bacterial metabolism. These compounds were further affected (P < 0.05) by cooking (decrease of about 10 to 30 percent). Phytosterols were not affected during processing. Enriched yogurt had lower syneresis comparing to the control yogurt during storage (P < 0.05). Lower syneresis in enriched yogurt was probably due to higher total solids (TS) and the gel network, being DPC