Utilization of watermelon rind waste as a potential source of dietary fiber to improve health promoting properties and reduce glycemic index for cookie making

Watermelon rind powder (WRP) is a rich source of dietary fiber and bioactive compounds, hence it could be used in the development of functional foods such as cookies. Different replacement levels of wheat flour with either WRP or hi-maize starch (HMS) (10-30%) on the quality of the cookies made were studied. The dietary fiber content in the cookies increased with incorporation of increasing level of either WRP or HMS. Increasing the proportion of the WRP in the cookie making resulted in an increase in the total phenolic content, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, and the ferric reducing antioxidant power. Using up to 20% of WRP and 30% of HMS in the cookie making promotes: increase in dietary fiber, decrease in predicted glycemic index to medium (for WRP) and low (for HMS) levels, and improving the antioxidant activity. These changes still produce an acceptable cookie.     

Effect of storage proteins on pasting properties and microstructure of Thai rice

This study investigated the influences of rice storage proteins, in relation to amylose content, on pasting properties of newly harvested Thai rice. The polished rice cultivars investigated included waxy rice SPT1, which contained 1.3% amylose and 8.3% protein; and non-waxy rice, namely PTT1 and LPT123, which contained 14.1% and 28.6% amylose, and 6.7% and 9.6% protein, respectively. The characteristics of protein fractions were altered by accelerated aging at 60 °C and 70% relative humidity (RH) for 5 days, and/or by alkali deproteinisation and cysteine addition during Rapid Visco Analyser (RVA) pasting characterisation. Accelerated aging, deproteinisation and the reduction of disulfide bonds changed the RVA pasting curves of all Thai rice cultivars, particularly the waxy one (p < 0.05). This study has quantified the contribution of protein in relation to amylose on the RVA pasting profiles and demonstrated that protein and starch were in separated phases after heating. The continuity of the protein network in cooked non-waxy rice grains observed under confocal laser scanning microscopy (CLSM) indicated bi-continuous structure of starch and protein phases.     

Effect of high‐pressure microfluidization on the structure of cassava starch granule

Microfluidization has been applied to modify starch granules. The study was conducted to investigate the effect of microfluidization on the structure and thermal properties of cassava starch–water suspension (20% w/w). The means of optical microscopy, SEM, FTIR spectroscopy, XRD, and DSC were applied to analyze the changes in microstructure, crystallinity, and thermal property. Microscopy observations revealed that native starch granules were oval, round, and truncated in shape. After the microfluidization treatment, a bigger starch granule was partially gelatinized, and a gel‐like structure was formed on a granular surface. No significant difference in XRD patterns of the samples were observed and all samples exhibited A‐type allomorph. Crystallinity decreased with the pressure. Sample treated at 150 MPa contains 17.1% crystalline glucan polymer, lower than that of native granules which have crystallinity of about 25.8%. A lower crystallinity means poor order of crystalline glucan polymer structure in starch granules. The disruption of crystalline order within the granule was also observed by FTIR measurement. Thermal analysis using DSC indicated that the microfluidization treatment brought about a significant decrease of melting enthalpy. The gelatinization enthalpy was 12.0 and 3.0 J/g for the native sample and samples treated under the 150 MPa, respectively. The results indicate that high‐pressure microfluidization process induced the gelatinization of cassava starch, which is evaluated by a percentage of the degree of gelatinization, due to a pronounced decrease with increasing microfluidizing pressure.     

Microencapsulation of probiotic Lactobacillus brevis ST-69 producing GABA using alginate supplemented with nanocrystalline starch

Food Science and Biotechnology - Microencapsulation technology can be used to improve the probiotic viability under stress condition in the human gastrointestinal tract and during storage. The...