Kumudhini Akasapu

Influence of Blanching and Drying Parameters (Objective 1)

Six winter and six summer vegetables being abundantly produced in North-east India have been chosen for the present work. Overall methodology adopted for objective 1 is depicted in Figure 1.

Fig. 1: Methodology associated to the evaluation of blanching and drying parameters of summer and winter vegetables

All the vegetables were subjected to either blanching or drying and blanching followed by drying toinvestigate the effect of these treatments on chosen variables and identify the optimal drying time. All these vegetables are highly nutritious and are good sources of antioxidants, vitamins, and fibre. But at the same time, they are perishable in nature due to their high moisture content. Adequate processing is necessary to reduce the moisture content and enhance their shelf life while preserving the nutritional components as they are sensitive to heat and oxidation that may occur during processing. Thus, it is important to carry out the blanching and drying treatments at optimal parameters for achieving desired changes and maximum retention of nutrients. Considering these factors, appropriate blanching and drying parameters summarized in Table 1 have been set based on available prior art. Thereby relevant bias was set to achieve optimal drying time.

Table 1: Parameters and Variables summary of investigations targeting blanching and drying process evaluation

S.No	Treatment	Independent Variable or parameter	Dependent variables
1	Blanching	Temperature Time	Critical Dependent Variables: Moisture content Antioxidant activity Dependent Variables: Vitamin C Crude fibre Yield
2	Drying	Temperature Air velocity Time

Findings obtained in this objective will serve as a guideline for choosing the vegetables to be used in maximum and minimum quantities for the formulation of optimal vegetable soup mixes.

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Identification of preliminary best summer and winter vegetable based soup mix formulations (Objective 2)

This objective mainly targets the identification of preliminary best summer and winter vegetable soup mixes. As both the nutritional and sensory aspects play an important role in achieving a soup mix with good consumer acceptability, it is essential to balance both the aspects during the development of soup mix formulation. As previous findings provided useful inferences on the selection of vegetables based on their nutritional composition, this objective focuses on the sensory optimization based best vegetable mix combination selection. To achieve this sensory evaluation of 20 summer vegetable formulations and 20 winter vegetable formulations was carried out using two different sensory evaluation techniques. The sensory scores obtained for all the formulations were compared with that of a control (commercial) formulation and 5 best summer and winter formulations were selected. These were further filtered through nutritional characterization and 2 best soup mixes each from summer and winter vegetable-based formulations were selected. In the further studies, these formulations will be considered for mixture model based statistical optimization.

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To evaluate the role of various sensory evaluation techniques in optimization of vegetable mix to corn flour to spice mix ratio (Objective 3)

The main aim of this work is to achieve a soup mix composition with higher proportion of vegetable mix through a systematic approach. To achieve this, the vegetable soup mix combination with 25% vegetable proportion identified as the best in the previous objective was further optimized by varying the ratios of vegetable mix, corn flour and spice mix. Trial and error methodology was followed and the soup formulation was optimized targeting sensory properties. In this regard, three sensory evaluation techniques namely, 9-point hedonic scale, score deviation and fuzzy logic methods were used to identify the optimal soup mix formulations. Finally, the formulations were assigned ranks based on the scores obtained through each sensory evaluation technique and the best formulation was identified. This work provided useful insights on the role of chosen sensory evaluation technique in optimization of vegetable soup mix, their advantages and limitations.

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To optimize vegetable mix constitution with respect to antioxidant activity and sensory scores using RSM based mixture model and to evaluate nutritional characteristics and invitro bioavailability (Objective 4)

This work targets the statistical based optimization of the vegetable proportion using D-optimal mixture model design (MMD). As MMD has an advantage of optimizing an entire mixture of various constituents within a total concentration of 100%, this design is known to be more suitable for optimization of a particular portion in a 100% mix or the entire 100% mixture. Thus, in this work work, three vegetables of the vegetable mix in a soup formulation were considered as three variables (constraints) for optimization whereas corn flour and spice mix were considered as fixed constraints. Entire soup mix with these three ingredients was considered as a mixture of 100%. Vegetable mix composition was optimized in terms of antioxidant activity and sensory scores. Finally, the optimal soup mix was analysed for nutritional characteristics, mineral content and invitro bioavailability of nutrients. This work provided useful understandings of the application and feasibility of mixture model based statistical technique in the optimization of soup mix formulation with respect to nutritional and sensory properties.

Further details are mentioned in research statement