Efeito da adição de concentrado proteico de soro e leite em po desnatado na fabricação de iogurte firme

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The increase in the levei of milk solids used in the manufacturing of yogurt is a common practice and it seeks to improve the firmness and to reduce product syneresis. The objective of this study was to compare the fermentation characteristics during the process of production of the yogurt, the texture profile, the susceptibility to syneresis and post-acidification along the time and sensorial characteristics of the set yogurts manufactured with the addition of skim milk powder (SMP) or whey protein concentrate (WPC) in different concentrations. A Split-Plot design with three replicate was used. The milk was divided in portions and five treatments were applied at random in the portions. The treatments were the following: without addition of solids and with addition of SMP or form WPC in order to increase the levei of solids to 13 and 15%.During the fermentactive process were retired samples of the products every 15 minutes for pH and acidity determination. The time of fermentation was considered necessary for the product to reach pH 4,6. The products were stored in plastic container to 4°C and randomly chosen after 1, 8, 16 and 23 days of manufacturing and evaluated for texture profile (firmness, springiness and cohesiveness), susceptibility to syneresis, pH and acidity. Afier the manufacturing, the yogurts were analyzed for total solids, protein, fat, lactose and ash. The yogurts without addition of solids, with addition of SMP or WPC in order to increase the level of solids to 13 and 15% presented, respectively, 11.13, 13.O1, 14.98, 13.04 and 15.04% of total solids; 3.05, 4.05, 4.43, 3.94 and 4.49% of proteins; 3.11, 3.09, 3.04, 3.21 and 3.11% of fat; 4.22, 4.91,6.34,4.94 and 6.33% of lactose; 0.75, 0.97,1.17,0.95 and 1.11% of ash. In the same previous order the products, during the fermentation process presented, respectively, 6.48, 6.5, 6.49, 6.47 and 6.53 of initial pH; 0.17, 0.19, 0.23, 0.18 and 0.22% of initial acid lactic; 4.61, 4.59, 4.60, 4.61 and 4.60 of final pH; 0.64, 0.80, 0.89, 0.72 and 0.84% of finallactic acid and 165, 195, 185, 165 and 185 min of fermentation time. The yogurts with SMP were significantly more firmer and the firmness of ali products increased in a significantly way during storage. The springiness and the cohesineness of the products were significantly influenced by the different treatments, even so only the cohesineness was significantly influenced during storage. Yogurts with addítion of WPC and 13% of total solids presented significant reduction of the syneresis during storage, differing from the other products, which presented a significant increase of syneresis during storage. The products to which SMP or WPC were added in order to increase the level of solids for 15%, presented, respectively, the greatest (29,86) and the smallest (9,13) percentage of increase of syneresis during storage períod.The treatments didn t significantly influenced the post-acidification of the products, which were significantly influenced by storage period. The substitution of SMP for WPC to increase the levei of solids in milk used for the manufacturing of set yogurt resulted in less firm products, with less syneresis and no changes ín post-acidification. The sensorial analysis showed that the yogurts obtained with addition of SMP were better accepted by the consumers and it had 60% of choice preference approximately in relation to the other yogurts with addition of WPC and without addition of solids

ASSUNTO(S)

leite em po iogurte

ACESSO AO ARTIGO

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