Tempering is one of the most important processes in chocolate making. Tempering is needed to ensure that chocolate has correct melting point, hardness, snap and gloss. After tempering, cocoa butter crystallises in polymorphic form beta V, resulting in chocolate with melting point in the range of 33-34°C. This work investigated the impact of crystal maturation duration and holding time of tempering process on hardness and appearance of dark chocolate. Five durations of crystal maturation, namely 1,3,5,and 7 days and five holding time namely 3,6,9,12,15 and minutes were used as variables. The results showed that hardness of chocolate had propensity to increase as the maturation duration was prolonged. Similar trend was also observed as the holding time increased. With regard to the colour, the L*, a* and b* values tended to decrease as the duration of crystal maturation increased. The use oven method, thus, seemed to have potential for small-scale production of dark chocolate.

Chocolate easily melts at a temperature of 32-34°C. This is a challenge for tropical countries, such as Indonesia. To cope with this problem, an innovation is needed to produce a heat-resistant chocolate. One of methods that can be done is by adding hydrogel. The purpose of this research was to investigate the effect of hydrogel made from konjac glucomannan on the physical characteristics of chocolate. In this study, hydrogel with a proportion of 2% was added into chocolate at the end of conching process. The influence of three different hydrogels made with konjac glucomannan concentration of 3%, 5%, and 7% was investigated. The result showed that the addition of hydrogel had a significant effect on the characteristics of chocolate. The addition of hydrogel did not only increase the melting point of chocolate, but also increased the hardness and particle size of chocolate. The higher the hydrogel concentration, the higher the hardness values. In conclusion, the addition of konjac glucomannan-based hydrogel in chocolate has the potential to produce heat-resistant chocolate.

Flow properties of chocolate highly determine mouthfeel and consumer acceptance. Aside from these, they are also important factors in determining the incorporation of chocolate in food products. This work investigated the possibility of using viscometer to determine the flow properties of molten chocolate. The data obtained from viscometer was fitted to Casson Model. Afterwards, Casson yield value and Casson viscosity were then derived. To observe the homogeneity of molten chocolate, thixotropy value was also determined. In this study, molten chocolate was produced using a stone melanger as an alternative processing method. Four grinding durations, namely 4, 8, 12, and 16 hours, were used to produce 4 types of dark chocolate. The results showed that viscometer was able to determine the value of Casson Model parameters, eventhough the shear rate reached was only approximately 45 s−1. Using this approach, it can be observed that the Casson Yield Value and Casson Viscosity increased as the grinding durations were increased.

Melting temperature of chocolate needs to be increased since it easily melts at temperatures below 34 o C. An elevated melting temperature gives benefits for chocolate producers in tropical countries. In this study, heat-resistant chocolate was developed using indirect incorporation of water. Xanthan Gum-based hydrogel was added into chocolate in the end of conching process with the proportion of 2%. This work aimed to investigate the impact of Xanthan Gum-based hydrogel on the properties of chocolate. The influence of three different Xanthan Gum-based hydrogels concentration, namely 3%, 5%, and 7% was investigated. The results showed that, due to a high moisture content and melting values of chocolates increased.

Chicken meat has a high nutrient content. However, its quality is easy to be degraded. The degradation is normally characterized by the formation of metabolite gases (NH3 and H2S) as deterioration indicators. Sensors detect phenomena better than human senses. This study aimed to classify meat quality based on gas formation during meat storage. In addition, a kinetics model of gas changes was determined. The gases were detected using a set of equipment consisting of Raspberry Pi and Metal-Oxide-Semiconductor (MOS) gas sensors. Samples were put in a 10 x 10 x 10 (cm) black container. MOS sensors were put inside the box to detect the gases at room temperature for 24 hours, with data collection being recorded every hour. Obtained data were then analyzed using Principle Component Analysis (PCA) for quality classification. The study showed that the quality of chicken meat was classified into three groups with a total variance of more than 95%. PC1 explained 88.2%, and PC2 explained 9.0%. The constant rate of H2S and NH3 changes followed the first-order kinetics with a constant rate of 0.2641 and 0.2925, respectively. The equation for H2S and NH3 changes were Ct=1.70 e0.2641 t and Ct=1.00 e0.2925 t, respectively. Keywords: Chicken meat, Freshness, H2S gas, NH3 gas, Sensor