Effectiveness of convective drying to conserve indigenous yeasts with high volatile profile isolated from algerian fermented raw bovine milk (Rayeb)

Abstract

Yeasts Candida tropicalis, Yarrowia lipolytica, Wickerhamomyces anomalus, Issatchenkia orientalis, Kluyveromyces marxianus, Saprochaete suaveolens and Trichosporon coremiiforme were isolated and identified by physiological, biochemical tests with API 20C AUX system and molecular methods by restriction fragment analysis of PCR-amplified 28S-rRNA from Algerian fermented raw bovine milk (Rayeb). Selected yeasts S. suaveolens, I. orientalis, K. marxianus and W. anomalus produced esters and higher esters which can exert a pertinent influence on the sensory characteristics of Rayeb. Viability of S. suaveolens and W. anomalus using three methods of drying (freeze-drying, convective drying, and spray-drying) and during 4 months of storage at 4 °C and 25 °C in the darkness was studied. Immediately after each drying method, high survival was obtained using freeze-drying followed by convective drying in rice cakes and spray-drying respectively. During storage at 4 °C, convective drying provided better survival of yeast cultures of S. suaveolens and W. anomalus than freeze-drying. At 25 °C of storage, convective and freeze-dried yeast cultures showed no significant loss of viable cells up to 2 months of storage. Spray-dried yeast cultures had the greatest loss of viable count during the 3 months of storage at 25 °C.Keywords: Rayeb; yeasts; identification; volatile compounds; preservation methods.Practical Application: Conservation of selected yeasts that produce volatile compounds by convective air drying compared to high cost freeze-drying and spray-drying methods.

Characterization of physicochemical composition, microbiology, sensory evaluation and microscopical attributes of sweetened condensed milk

“…Despite the recent researches on dairy technology, science and nutrition (Akal & Yetişemiyen, 2016;Barbosa et al, 2013;Bosso et al, 2016;Hamoudi-Belarbi et al, 2016;Mostafidi et al, 2016;Rangel et al, 2016;Sales et al, 2016), there are few information's published on the sweetened condensed milk subject.…”

Inventoried Yeast Species in Algeria

“…27 identified species were isolated from dairy products. Y. lipolytica is isolated from all king of milk [81,93,94]. From fermented bovine milk 7 identified species are C. tropicalis, Issatchenkia orientalis (Syn.…”

Preservation of non‐Saccharomyces yeasts: Current technologies and challenges

“…Viability of G. fragrans and W. anomalus using two drying methods (convective and spray) and after 4 months of storage at 4 • C and 25 • C in the darkness was studied (Hamoudi-Belarbi et al, 2016). Convective air-drying rice cakes were made by drying rice dough at 40 • C in a convective air-drying oven for 5 hr.…”

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