Waraporn Boonsupthip

Preparation of Polydiacetylene Vesicle and Amphiphilic Polymer as Time-Temperature Indicator

Polydiacetylene (PDA) was used as a colorimetric indicator depended on temperature and time. This paper presents a new time-temperature indicator based on PDA vesicle and amphiphilic polymer. The 10,12-pentacosadiynoic acid (PCDA) was prepared with different concentration of Pluronic F127 which was varied from 0 to 4 % w/v, respectively. After that, there was obtained in different temperature (30-50°C) until clearly color change. This solution could gradually change from blue to red color which it could observe by UV-Vis spectrophotometer. The absorbance in each solution was reported at 640 and 540 nm, respectively, and then calculated by the color response (CR). In addition, the CR increased that directly related with temperature and time, when the concentration of F127 was constant. Also, the CR increased that directly related with temperature and concentration of F127, when time was constant. This method could have potential application as a new time-temperature indicator.

Use of average molecular weights for product categories to predict freezing characteristics of foods.

In the design of food freezing process, food property parameters, initial freezing temperature (T(Fi)), and frozen water fraction (X(I)) are required. The predictive approaches of these 2 parameters have been developed based on mass fractions and molecular weights of specific food components such as proteins, carbohydrates, minerals, and acids/bases. In this study, the molecular weights of the key mineral and acid/base components were successfully represented using average molecular weights (M) and 4 T(Fi) and X(I) calculation approaches were proposed. Based on an analysis of 212 food products, the absolute differences (AD) between the experimental and predicted T(Fi) values for the 4 approaches were small. The prediction for the food model category was excellent with average AD values as low as +/- 0.03 degrees C. For the other food categories, the prediction efficiency was impressive with values between +/- 0.22 and +/- 0.38 degrees C. The predicted relationship between temperature and X(I) for all analyzed food products provided close agreements with experimental data.

Effect of air temperature and velocity on moisture diffusivity in relation to physical and sensory quality of dried pumpkin seeds

ABSTRACT Understanding the effect of drying process parameters on food quality is helpful in process optimization and control. The objective of this work is to understand the effect of mild and harsh effective moisture diffusivity (Deff), varied by air temperature and velocity, of drying processes on the physical and sensory quality of flat food products. Pumpkin seeds were selected as a food representative. It was found that increments of air temperature and velocity resulted in increased Deff and brown color on seed hull surfaces and embryos, but decreased hardness of seed embryos. Changes in taste and aroma of seed embryos were able to be sensed. Indicating that Deff is related to seed physical quality. Similar phenomena occurred with both tray and fluidized bed drying. Air temperature, velocity, and Deff should be controlled to ensure the best dried flat food products. Mild drying conditions are potentially preferred for good physical and sensory quality.

Mathematical Modeling of Browning Induction Period in Drying Onion as Influenced by Temperature, Equilibrium Relative Humidity, and Inhibitor

This work focused on the browning induction period (BIP) during onion drying and understanding the impact of selected static conditions and cyclodextrin addition on the BIP. Under static conditions (between 40 and 80°C and betwen 0.11 and 0.98 equilibrium relative humidity, ERH), the BIP due to nonenzymatic reactions was evident but apparently reduced by enzymatic browning reactions at 40°C. Cyclodextrin usually inhibited browning from both reactions under some conditions, whereas it stimulated browning under the combined conditions of an ERH of 0.58 and 0.75 and temperatures of 40 and 60°C. The proposed interaction polynomial models successfully cover both enzymatic and nonenzymatic browning experienced at the initially low and then high temperatures used in food drying. These models can be useful for a food drying process design to minimize browning.

Improved Temperature Homogeneity of Cake Batter and Cake Quality with Reduction in Heat Conductivity of the Baking Pan at the Ends

ABSTRACT With high competition in bakery markets, baking process improvements in efficiency are necessary. Sliced butter cake is a well-known bakery product. It is baked in a long, rectangular aluminum pan in which it is difficult to manage homogeneous heat distribution throughout the whole cake. Alteration of pan thermal properties through the Biot number concept (reducing thermal conductivity at the ends of the pan to increase Bi to 1.30) improved homogeneity of the heat distribution as well as the cake qualities throughout the whole cake piece by modifying the cake properties at the problematic location adjacent to the ends of the pan (hot zones, where crust thickness was reduced from 0.32 to 0.23 cm, cake height increased from 6.8 to 7.4 cm, and cake and crust colors improved). Waste from size defects (cake height too short and crust too thick) of butter cake in the hot zones was also reduced. The sensory results revealed improvement in the softness, moistness, and overall liking of the cake. Higher h...

Physical, Chemical, and Sensory Properties of Antioxidant-Enriched Raw and Cooked Rice by Vacuum-Drying Impregnation in a Semidry State

ABSTRACT Vacuum drying was employed with a vacuum impregnation technique in a semidry state to enrich rice with antioxidants of beetroot juice. The properties of the vacuum-dried raw and cooked rice grains were characterized. The various raw rice grains (three varieties and two storage time periods) exhibited a significant absorption of beetroot juice, which was evident from the red-violet beetroot color of the rice, as distinguished from the white color of the control. The color increase (ΔE= 20−40) was linear with the juice content (R2 = 0.96−0.99). Their total phenolic (TP) contents and 2,2-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activities were enhanced (ΔTP = 21−260 mg of gallic acid equivalents/100 g of rice db and ΔDPPH = 22−64 mg of vitamin C equivalents/100 g of rice db). Their grain integrity was reduced (Δforce = −1 to −63), which was potentially associated with the formation of grain surface cracks (linear relationship of %crack and %juice with R2 = 0.94−0.98). After cooking, the e...