Bebidas de Kefir com e sem inulina em versões integral e desnatada : elaboração e caracterização química, física, microbiológica e sensorial

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

01/09/2010

RESUMO

The beverage Kefir is a result of fermentation of milk by lactic acid bacteria, aceticacid bacteria and yeasts contained in Kefir grains or in lyophilized starter culture. Besides bacteria and yeasts, the beverage contains minerals, vitamins B and essential amino acids, important for the maintenance of the vital functions of the organism. The beverage consumption can relieve intestinal disorders and reduce flatulence promoting a healthier intestinal system. The inulin is considered a prebiotic and acts as a fat substitute. The influence of fat content, fermentation initiators, grains or Kefir starter culture, and the addition of 2 % of inulin and cold storage (4° C) in the chemical characteristics (composition and acidity) physical characteristics (color, firmness, syneresis and viscosity), microbiological characteristics (counts oflactic acid bacteria, acetic acid bacteria, yeasts and total coliforms at 45° C) and sensorial characteristics (sensorial profile and acceptability) were investigated, through eight formulations (1 e 2, full fat and Kefir grains; 3 e 4, full fat and starterculture; 5 e 6, low-fat and Kefir grains e 7 e 8, low- fat and starter culture. Theformulations 2, 4, 6 e 8 contained 2 % of inulin. Saccharose ( 8% w/v) was added inthe formulations for the sensorial analysis. Eighteen trained tasters participated in the Quantitative Descriptive Analysis (QDA) and fifty consumers in the acceptability test.The data were submitted to the ANOVA, Tukey test, Pearson Correlations and Analysis of Main Components. The inulin was not hidrolized during the fermentation process. The pH varied from 4,60 to 4,36 and acidity was similar (0,93%). The low-fatbeverage were less yellowish (b* = 3,76), with lower lactose content (2,9 g/100g) andhigher syneresis (31,81 g/100g) than full-fat beverages (b* = 5,8, lactose = 3,2g/100g, syneresis = 26,9 g/100g). The full-fat fermented formulations with starterculture, with or without inulin were firmer and more viscous (firmness = 1,80 N,viscosity between 5300 and 3342 cP) than low-fat fermented beverages with Kefirgrains, with and without inulin (firmness = 0,35 N, viscosity = 2527 cP). The counts oflactic acid and acetic acid bacteria, and yeasts in the formulations indicatedvariations, making it impossible to identify the influence of fat content, fermentationinitiator or inulin. The addition of saccharose and the homogenization processpresented a decrease in firmness and viscosity of the beverages. In the Quantitative Descriptive Analysis, the first principal component of PCA (54% explanation) separated the formulations regarding the initiators of the fermentation and the secondcomponent (24,2 % of explanation) regarding fat content. The full-fat beveragesfermented with grains presented grainy appearance and rather homogeneoustexture, and the beverages fermented with starter culture, indicated morecreaminess, viscosity, consistency and a yellowish color. The low-fat beverages fermented with grains presented a higher level taste and flavor and aroma but less consistency, creaminess and viscosity while the beverages fermented with starter culture, presented sweet aroma and taste and more intense homogeneity, besides a less intense granular texture. The beverages presented a moderated level of acceptance (value between 6 and 7 in scale of 9 points). The formulation with full fat milk, starter culture and inulin indicated a higher acceptance level than low-fatbeverages fermented with Kefir grains and without inulin. The storage resulted in adecrease of 8 % in content of inulin in the full-fat beverages and 9% in low-fat, and 33 % of lactose for low-fat and from 40 to 29% for the full-fat. There was a decreasein pH from 4,80 to 4,07 (full-fat) and from 4,79 to 4,15 (low-fat) and an increase ofacidity level from 0,90 to 1,43 % (full-fat) and from 0,95 to 1,39 % (low-fat) in the formulations fermented with grains. In formulations fermented with culture was oscillation pH (between 4,58 and 4,69 in full-fat and from 4,54 to 4,58 in low-fat) and acidity level (between 0,90 and 0,86 in full-fat and between 0,97 and 0,92 in lowfat). In general, the firmness increased from 0,45 to 0,58 N in full-fat fermented with grains, from 1,80 to 2,07 N in full-fat fermented with starter culture, from 0,35 to 0,74N in low-fat fermented with Kefir grains and from 1,39 to 1,62 N in low-fat fermented with starter culture, syneresis from 25,94 to 26,03 g/100g in full-fat and from 31,81 to37,45 g/100g in low-fat. The viscosity level incresed from 4136,18 to 4434,0 cP infull-fat and from 2878,75 to 2202,7 cP in low-fat. The counts of lactic acid bacteria, acetic acid bacteria and yeasts oscillated between 8 and 12 log UFC g-1. The presence of coliforms was not detected in the beverages within the first and in the28° day of storage.

ASSUNTO(S)

bebidas fermentadas grãos de kefir inulina alimentos - avaliação sensorial brewing grain inulin food sensory evaluation

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