Browsing by Subject "mixture design"

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  • Ouedrhiri, Wessal; Mechchate, Hamza; Moja, Sandrine; Mothana, Ramzi A.; Noman, Omar M.; Grafov, Andriy; Greche, Hassane (2021)
    Several studies have demonstrated the possible synergistic effect as an effective strategy to boost the bioactivity of essential oils. Using this framework, this study was conducted to effectively establish the ideal combination of six essential oils from different plants (Origanum compactum, Origanum majorana, Thymus serpyllum, Mentha spicata, Myrtus communis, and Artemisia herba-alba) that would express the best antioxidant activity. Each mixture was optimized using a mixture design approach to generate the most effective blend. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging method was used as a reference method to assess the antioxidant activity. Each essential oil's composition was identified using the GC/MS method. The single essential oil activities demonstrated variable antioxidant effects, and following the mixture design approach, the optimal antioxidant blend was revealed, as two mixtures demonstrated the best antiradical activity with 79.46% obtained with the mixture of O. majorana (28%) and M. spicata (71%) and 78.8% obtained with the mixture O. compactum (64%), O. majorana (13%), and T. serpyllum (21%). This study proposes a practical way to elaborate mixtures in the search for a boosting effect that can be oriented for the food or pharmaceutical industry.
  • Liukkonen, Tanja (Helsingfors universitet, 2015)
    Gelatin-based confections are one type of gummy confections. Their main ingredients are water, sucrose, glucose syrup and gelatin, which causes gel-like texture. The literature review focused on the raw materials, the manufacturing process and the properties of gelatin- and starch-based gummy confections. The aim of this study was to find out how invert sugar, when it replaces sucrose and glucose syrup, affects structural properties and short-term shelf life of gelatin-based confections. In addition, changes in the sensory quality were observed. In the experimental research, the gelatin-based confections were manufactured on a laboratory scale according to simplex-centroid mixture design, where the total sugar content was constant, but sucrose, glucose syrup and invert sugar mass fractions were varied. Measurements for the samples were rheological properties, sugar content and dry matter content of confection paste and mechanical properties (hardness, stickiness and relaxation parameters), dry matter content, water activity and water sorption of confections. In addition, a few samples were manufactured with coloring and flavoring agents for sensory observation. The results were analyzed with the PLSR (Partial Least Squares Regression). Finnsugar Ltd.'s product development department offered the topic of this study and raw materials, but all the experiments were carried out in the Department of Food and Environmental Sciences in the University of Helsinki. The PLSR model contained five components, and the coefficient of determination R2 was 74.1%, the adjusted R2 was 63.3% and the coefficient of prediction Q2 was 43.6%. The model determined all response variables well, but predicted some of them poorly. Almost all response variables regression models were statistically significant at 5% significance level, but some of the models were incomplete (plof<0.05). The variables important in projection (VIP) in the PLSR model were mass fraction of invert sugar, mass fraction of glucose syrup and their interactions with mass fraction of sucrose. The PLSR model was best for rheological properties of confection pastes and mechanical properties of confections, and poorest for water activity and dry matter content of confections. Even at low mass fraction of invert sugar viscosity of confection paste decreased. Invert sugar also reduced hardness of confections, and speeded up their structures recovery after compression. Sensory observation shows the positive effects of invert sugar, such as softness of structure and stronger taste. The present study showed that the sugars have interactions, which also affect properties of the gelatin-based confections, and invert sugar content alone is not the significant factor. Based on the results of this study it seems that invert sugar affected stronger most of the response variables if it replaced relatively more glucose syrup than sucrose.
  • Liu, Yu (Helsingin yliopisto, 2021)
    A growing population is suffering from protein insufficiency and seas of over-fishing. On the other hand, an abundant amount of low-value or underutilized fish species remains unexploited for human consumption mainly due to low consumer preferences. For this reason, new solutions are needed to utilize these fish better. This study was carried out in two phases. In phase I, extrudates from five underutilized fish species and pea protein isolate (PPI) were produced by using a high-moisture extrusion process (HMEP). The aim was to successfully produce extrudates and study their sensory and texture properties by generic descriptive analysis (GDA), instrumental color measurements, and instrumental tensile strength measurements. In phase II, PPI was partially replaced in the recipe by two cereal fractions. The experiment was generated by simplex-centroid mixture design to study the effects of PPI and two cereal fractions on the texture of extrudates. The results of phase I showed that the extrudates were successfully produced. Extrudates from Baltic herring were one extreme with intense flavor and odor, such as seaweed, and the highest fracturability. Smelt extrudates were another extreme with intense flavor, odor, and greyness. For further studies, a combination of the present analytical sensory profiling data and the hedonic response of consumers will be needed for the product development. In phase II, the extrudates produced from a low amount of PPI with a high amount of cereal fractions were doughy and too soft. Other ingredients should be considered in further studies to replace PPI.