Influence of Avocado Puree as a Fat Replacer on Physico-chemical and Sensory Properties of Chocolate Cake

Choo, Kah Wen (2020) Influence of Avocado Puree as a Fat Replacer on Physico-chemical and Sensory Properties of Chocolate Cake. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

The aim of this study was to investigate the effect of addition avocado puree into chocolate cake on the physicochemical properties, nutritional characteristics, microbiological quality and sensory properties. Five formulations were designed which includedF0 (replaced with 0% avocado puree, which is control), F1 (replaced with 25% avocado puree), F2 (replaced with 50% avocado puree), F3 (replaced with 75% avocado puree) and F4 (replacedwith 100% avocado puree). In this study, the physical properties was carried out to evaluate the specific gravity of batter, baking loss, height, color, water activity and texture of chocolate cakes by AquaLab, texture profile analyser, and Lovibond Spectrocolorimeter. Specific gravity and water activity increased significantly (p < 0.05) as compared to F0. There is no significant different (p > 0.05) in baking loss and height as well. Furthermore, L*, a*, b* values in F0 was significantly highest (p < 0.05) among avocado-replaced chocolate cakes. This indicated that there were darker, less red and less yellow in the chocolate cakes as the avocado replacement level increased. Moreover, textural measurement showed F4 which is full substitution was significantly (p < 0.05) highest in hardness, cohesiveness and chewiness among other samples. There was no significant difference (p > 0.05) in springiness due to insignificant values obtained.Besides, proximate analysis was done which included Soxhlet method, Kjeldahl method, acid and alkaline digestion method, dry ashing and oven drying to determine the content of fat, crude protein, crude fiber, ash, moisture content and carbohydrate. As compared to control, avocado-replaced chocolate cakes had greater moisture, crude protein and crude fiber; lower fat and ash at (p < 0.05) with the increase in avocado replacement level. However, carbohydrate decreased insignificantly (p > 0.05). DPPH free radical assay, Folin-ciocalteu method and peroxide value assay were also done to determine the antioxidant activity, total phenolics and peroxide value in the samples. Result showed significant different (p < 0.05) in terms of antioxidant activity, total phenolics and peroxide value. They increased with addition of avocado puree in the chocolate cake. Additionally, sensory evaluation such as 9-point hedonic scale and preference test were conducted in the sensory room. Control showed significant difference in taste, texture and overall acceptance but insignificant difference (p > 0.05) in color and aroma. In preference test, F2 obtained highest percentage which is 44% among others. Last but not least, microbiological analysis such as total plate count method was carried out to determine the shelf-life of the cake. Microbial load reduced as the avocado replacement level increased and it was in the acceptable range.