Pengaruh Heat Moisture Treatment terhadap Laju Retrogradasi pada Gel Pati Sagu (Metroxylon sp.) dan Pati Aren (Arenga pinnata)

Abstract

Starch is a carbohydrate reserves that are found in various plants and is the second largest source of carbohydrates after cellulose. One starch derived from palm. As for example of the palm starch sources is sago (Metroxylon sp) and sugar palm (Arenga pinnata). Native starch usually has a limited functional properties for a specific process. Modification of starch is usually done to improve the functional properties of starch for a particular purpose. Physical modification such as heat moisture treatment (HMT) has the potential to increase the functional properties of native starch. The purpose of this research was to study the effects of HMT on the rate of starch retrogradasi through the rate of sineresys, the changing textural properties, water content and water activity (aw) during storage. Modification of HMT performed with the method of autoclaving at a temperature of 60 minutes 120oC to sago starch and 90 minutes for arenga starch where previously made starch moisture content of 20%. The rate of sineresis was measured by using centrifuge method, whereas the characteristics of the texture was measured by using texture analyzer. Further analysis was the measurement of water content of starch gels using the oven method and measurement of water activity (aw) using the aw meters. Result of RVA measurement show that HMT can increase the gelatinization temperature, lower breakdown and increasing the setback. This research proved that HMT increases the rate of sineresis of sago and arenga starch gel and can make the texture more rigid. In addition, modification of HMT also increases the fragility of the gels and the moisture content was decreases. Decreasing in aw also occur due to the influence of the HMT. The value of the lowest aw occurred at Sagu HMT starch gel although the rate of decline in the value of the highest aw occurs in the sagu alami starch. Based on the results of the study it can be concluded that the Sagu HMT starch sensitive to heat treatment compared to Aren HMT starch, sagu alami and arenga starch. This is apparent from the highest of increasing a rate of syneresis, increasing in the rate of the elastic modulus, the highest of declining the rate of the strains value, and the highest of the rate of gel moisture content decreasing.