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Browsing by Subject "yogurt"

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  • Faba bean protein stabilized emulsion and gel 
    Xu, Yi (2023)
    The literature review detailed the theoretical background for this study, identified the possibility about development of faba bean protein stabilized emulsion for food products and studied the effect of increased oil addition on the structure of emulsions. The practical work was divided into three parts emulsion analysis, emulsion gel analysis and sensory evaluation. Various research methods were applie d to support this study, including droplet size distribution , droplet charge ζ potential), texture evaluation, and rheological analysis. This study showed that oil addition increased emulsion droplet size, as well as the absolute value of ζ potential . Emulsifying activity index (EAI) and emulsion stability index (ESI) decreased with increasing oil concentration. F aba protein stabilized emulsions were better stabilized by oil addition , compared with those without oil additi on . From texture analysis of gel properties, firmness improved with increasing oil concentrations (0% 30%). In addition, rheolog ical analysis for faba yogurt samples showed that increasing oil concentrations improved the viscosity of the faba yogurt samples. T he results also illustrated that increasing oil concentrations led to increased deformation meaning the emulsion gels were more easily destroyed with increasing oil concentrations (0 30%). Oil addition resulted in higher whiteness when compared with samples without oil. Sensory evaluation by a professional panel for faba yogurt samples indicated that samples with 20% oil concentration w ere the most preferred and had the highest overall quality .
  • Jogurtin laadun hallinta 
    Helminen, Pirjo (2014)
    Thesis literature review deals with composition of cow´s milk, yogurt manufacturing, composition and process attributes affecting textural properties of yogurt and measuring textural properties of yogurt. Plain, stirred yogurts (kg) were manufactured at Valio Riihimäki and Oulu Dairies. The aim of the research was to find out attributes that affect yogurt quality. First milk base composition was determined and, yogurt textural properties were determined (viscosity, graininess, syneresis) using different techniques. Finally yogurt statistical relationships or Pearson correlations and statistical significance between yogurt textural properties and milk base composition and manufacturing process were determined. Additional objective was to determine common specification limits to yogurt textural properties. Statistical analysis; pearson correlation coefficients, p-value and specification limits were carried out using MINITAB®16 statistical software. Good yogurt texture is viscous, free from grains and syneresis. This study showed that yogurt textural properties (viscosity, graininess and syneresis) were affected significantly by yogurt manufacturing plant. There were a lot of fluctuations in yogurt textural properties. Consequently yogurt viscosity fluctuated over 50%, graininess approx. 25% and syneresis approx. 30%. According to this study, yogurts standing a long time before packaging, were less viscose or watery compared to those with shorter standing time prior to packaging. Graininess and evaporating process were found to correlate positively. Yogurts were with more grains when manufacturing process`s evaporating temperature and evaporating rate (l/h) were higher. The higher milk base fat and dry matter content (%) were found to correlate lesser whey separation in yogurt. In addition the higher evaporating rate was in the yogurt manufacturing process, the lesser whey separation was observed. Results from this research are useful for developing dairy processes concerning yogurt manufacturing.

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