Effects of drying methods on quality parameters of potato and red beetroot purée with Lactobacillus delbrueckii
2020
Mocanu, Gabriel-Dănuţ | Nistor, Oana-Viorela | Andronoiu, Doina Georgeta | Ceclu, Liliana | Gheonea, Ionica Dima | Mihalcea, Liliana | Barbu, Viorica Vasilica | Constantin, Oana Emilia | Pătra, Livia
The aim of this study was to investigate the influence of conventional and foam-mat drying methods on the quality parameters of a non-dairy solid product based on potato (Solanum tuberosum L.) and red beetroot (Beta vulgaris L.). The vegetable purée was used as a fermentation substrate for the potentially probiotic Lactobacillus delbrueckii subsp. bulgaricus Lb12 strain. The purée samples were evaluated for rheological, microstructural, microbiological and phyto chemical properties. Rheological low amplitude oscillatory measurements revealed low resistance to the applied strain (between 0.1 % and 1 %). The instrumental texture measurements revealed that the samples obtained by foam-mat drying were the most similar to the fresh purée (from 0.6 ± 0.04 N to 1.6 ± 0.14 N). Confocal laser microscopy revealed vegetal tissues fragments with a rich content of bioactive compounds and lactic acid bacteria aggregated in biofilms. The counts of Lb12 were above 107 CFU∙g-1 after 28 days of storage. The content of betaxanthins, b-carotene and lycopene of the samples varied from 1 100 ± 12 mg∙kg-1 to 2 160 ± 9 mg∙kg-1, from 69 470 ± 250 mg∙kg-1 to 5 940 ± 160 mg∙kg-1 and from 46 520 ± 14 mg∙kg-1 to 3 550 ± 270 mg∙kg-1, respectively.
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