Iogurte adicionado de concentrado protéico de soro de leite e farinha de linhaça: desenvolvimento, qualidade nutricional e sensorial

• Autor(a) principal: Bastiani, Maria Inês Dantas
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/412
• topic: Proteínas de soro; Iogurte; Linhaça; Whey protein; Yogurt; Flaxseed; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS

Health concerns have promoted research and development of healthy foods with functional properties, which, besides supplying nutrients, modulate key physiological functions in the body. The dairy industry is no exception to this trend. This study aimed to evaluate the effect of the addition of whey protein concentrate (WPC) and flaxseed meal (FM) on nutritional and sensory quality of yoghurt. Four yogurt formulations were developed using skim milk added with 1.5% WPC and 1%, 2% and 3% FM. The content of total dietary fiber and &#945;- linolenic acid (&#969;-3) in FM, the proximate composition and mineral concentration of the four formulations were analyzed, as well as product classification as nutrient source, according to criteria established by the Food Agriculture Department (FDA) and the Brazilian legislation. Yogurt protein quality was biologically assayed using the Protein Efficiency Ratio (PER), Net Protein Ratio (NPR), Food Efficiency Ratio (FER) and True Digestibility (TD), compared with the casein diet. Yogurt formulations were microbiologically analyzed and sensory profile was obtained by Quantitative Descriptive Analysis. Acceptance of formulations was evaluated by 100 tasters and analyzed by Internal Preference Map. Protein levels found in all formulations were above the levels established by the Brazilian legislation. FM increased the lipid contents in the yogurt, changing product classification from skim to semi-skim, favoring essential fatty acid profile, mainly in relation to &#969;-3 concentration. Considering a 200-g yogurt serving, the formulations containing 2% and 3% FM were classified as an excellent &#969;-3 source, and 1% FM as a good source. According to the Brazilian legislation, none of the three formulations added with FM was considered as source of dietary fiber, but can carry the claim "contains fiber." All yogurt formulations are sources of Ca and P and were considered as low content of Na. Biological assays showed that the products developed have excellent protein quality, as they had PER (p <0.05) higher than casein. The small difference between PER and NPR indicated that the protein levels of diets containing the yogurt formulations had adequate biological value to ensure growth and maintenance of body tissues. From the viewpoint of protein digestibility, the four formulations showed good nutritional quality and the increase in fiber level due to FM did not affect this parameter (p> 0.05). All yoghurt formulations met the legislation requirements referring to microbiological parameters. The attributes assessed by QDA to evaluate the yoghurts were characteristic flaxseed color, viscosity, characteristic flaxseed aroma, acid taste, sweet taste, residual flaxseed taste, characteristic flaxseed flavor and presence of particles. Samples were significantly different (p <0.05) for the attributes characteristic flaxseed color, characteristic flaxseed aroma, residual flaxseed taste and presence of particles. The formulation containing 3% FM showed higher viscosity than the control (p <0.05). The attributes sweet and acid taste did not contribute to sample differentiation. The formulations without FM and with 1% FM had the highest acceptance followed by the sample containing 2% FM. The yogurt with the highest FM concentration had the lowest acceptance. It can be affirmed therefore that the formulation added with 2% FM is a good option, as it has good consumer acceptance and high protein quality, low level of total lipids, mainly saturated fat, with excellent source of &#945;-linolenic fatty acid, containing fiber and low content of Na. These characteristics differentiate this yogurt from those available in the market because of its high potential to promote health, with prospects for adding nutritional and functional value to fermented dairy products.