Study On Evaluation System And Anti-Staling Technique Of Mochi

Mochi, also named wagashi, is a kind of glutinous rice cake primarily made of glutinousrice flour, sugar, water, etc. It enjoys a promising market because of such characteristics of itsstickiness, softness and elasticity. However, deterioration of its sensory quality occurs gradu-ally with aging of starch, which leads to a short shelf life of Mochi. Currently, research on an-ti-staling of Mochi is relatively rare and there is no standard evaluation system providing ref-erence and guidance for production practice and theoretical researches. Therefore, this thesisestablished the evaluation system of Mochi, optimized the craftsmanship and basic formula ofMochi, and carried out a study on the effect of compound s anti-staling additive on sensoryquality of Mochi so as to develop a Mochi which had a better sensory quality and a longershelf life.Firstly, under the guidance of the fuzzy mathematics theory and on basis of surveymethod,5evaluation indexes of Mochi were acquired and their respective weight were dis-tributed, i.e. hardness30%; chewiness20%; viscoelastic20%; texture structure15%; flavor15%. Besides, sensory evaluation table of Mochi was established and detailed descriptionswere given. Meanwhile, the correlation analysis on sensory evaluation and texture measure-ment revealed that the hardness, springiness and chewiness in TPA parameters were in closecorrelation to every index in sensory evaluation, and that hardness could be regarded as themost critical index of Mochi in storage, which further improved evaluation system of Mochi.Secondly, with sensory evaluation (fresh Mochi) and hardness of TPA (stored for3daysin room temperature) as indexes, this thesis found an optimal production route. Through sin-gle factor and orthogonal experiments on process parameters and basic formula, this thesisarrived at an optimal parameter as follows: soaking time (120minutes), cooking time (27.5minutes), stirring time (12.5minutes), and an optimal basic formula as shown below: water100%, sugar35%, salad oil5%,(glutinous rice flour100%as benchmark, all percentagesrefer to mass fraction). Under such condition, sensory evaluation scores of fresh Mochi was96.18and hardness of TPA was545.24grams after storage for3days in room temperature,consequently, so Mochi got better sensory quality and longer shelf life. Finally, on basis of the index of hardness of TPA (stored for7days in room temperature),single factor experiment using sugar, hydrophilic colloids and modified starch carryed outseveral additive which had better effect on anti-staling of Mochi. Then, through response sur-face experiment with three factors and three levels based on the principle of Box-Behnkendesign, this thesis worked out the optimal formula of compound anti-staling addictive, that is,Trehalose42.58%, Guar gum0.31%, Hydroxypropyl modified waxy starch34.27%,(totalflour100%as benchmark, all percentages refer to mass fraction). On the basis of the com-pound formula, sensory evaluation scores of fresh Mochi was95.64and hardness of TPA was351.99grams after storage for7days in room temperature, which were accorded with opti-mization predicted by software. In addition, by means of the accelerated shelf-life testing(ASLT), the shelf life of Mochi stored in room temperature was predicted to extend to2~3months.