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Three rice starches with different amylose contents (Glutinous: 1.4%, Jasmine: 15.0% and Chiang: 20.2%) were pregelatinized in a double drum dryer at 110, 117 and 123°C. Starch crystallinity was determined by X-ray diffractometry and Fourier transform infrared (FTIR) spectrometry. Rheological properties were assessed by a Rapid Visco Analyser (RVA) and rheometer. Pregelatinized starches obtained from Glutinous (PGS) and Jasmine rice (PJS) gave an RVA pasting profile with cold peak viscosity. At drum temperature 110°C, PGS and PJS showed X-ray patterns that were indicative of amorphous structures. However, pregelatinized Chiang rice starch (PCS) exhibited RVA hot peak viscosity and the presence of an amylose-lipid complex with remaining granule structure. The PCS had a lower water absorption index (WAI) and water solubility index (WSI) than PJS and PGS. After pregelatinization at increased drum temperature (117, 123°C), the PGS had a lower WAI, whereas PCS showed an opposite trend indicating lower degree of granule disruption. In addition, the cold peak viscosity of PGS and PJS decreased with increasing drum temperature. For all drum temperatures, the apparent viscosity at 25°C for PGS and PJS decreased with increasing shear rate, indicating shear-thinning behavior.

This work was aimed at investigating the effects of steaming time and different fractions of sago starch (0, 6, 12, 18 and 24%) in mixtures with cassava starch on the properties of crackers as compared to cassava crackers. In the hydrothermal process, the steaming period was varied from 25 to 120 min. The properties of raw starches, half-finished crackers (HFC) and puffed crackers (PC) were determined. Raw cassava starch had lower amylose content, smaller granule size, lower gelatinization and lower swelling power than sago starch. The properties of the raw starch mixtures varied according to the mixing proportions. Both sago starch content and steaming time influenced cracker quality, especially its expansion, which was related to the degree of gelatinization (DG). Increasing sago starch content caused decreased DG of HFC and hence decreased cracker expansion. Two groups of HFC were obtained; low DG (55–65%, 25-45 min steaming time) and high DG (>80%, 60-120 min steaming time) HFC. Generally the expansion increased as the DG increased – however, a too long steaming period (>75 min) again reduced expansion, apparently the thinner starch gel allowed collapse of the air cells. No treatment gave complete gelatinization; which could be due to insufficient water for starch to gelatinize.

Starches extracted from three Thai aromatic fruit seed, chempedak (Artocarpus integer), jackfruit (Artocarpus heterophyllus L.), and durian (Durio zibethinus L./ Murr) – with mung bean starch for comparison – were investigated for chemical compositions, amylose content, resistant starch content, granule morphology and size distribution, crystalline pattern, swelling power and solubility, pasting and thermal properties. The extracted starches were of very high purity. The fruit seed starches had lower amylose contents and much smaller granule size than mung bean starch and hence lower pasting viscosities. Chempedak and jackfruit seed starches were very similar in swelling power, solubility, gelatinization temperature and enthalpy, while the properties of durian seed starch were close to those of mung bean starch. The information obtained in this work could be very useful for food, pharmaceutical and cosmetics applications. Further study on other functional and molecular properties should be considered.

Summary A reproducible system has been developed for efficient plant regeneration, through somatic embryogenesis, from callus derived from mature seed scutella of the aromatic indica rice cultivar Pusa Basmati 1. Protein, lipid and starch contents of the grain (seeds) of somatic embryo-derived (R0) and seed-derived glasshouse- grown plants, were evaluated histochemically and using analytical procedures. Protein was most abundant in the sub-aleurone layers, but was also present in aleurone cells. Lipid was localised in the embryo and aleurone cells; starch granules were evenly and abundantly distributed in the endosperm cells, although smaller in size near the periphery of the endosperm. Histochemically, the distribution of storage products was similar in somatic embryo- and seed-derived plants. The lipid contents were similar for grains from the two plant populations, but starch content was higher (2 %) for somatic embryo-derived plants; protein content was higher (2 %) for seed-derived plants. In contrast, for R1 generation plants, there were no significant differences in protein, lipid and carbohydrate components of grain obtained from somatic embryo- and seed-derived plants. These studies form an important baseline for more detailed determinations of the nutritional status of grain produced by transgenic rice plants.

This study examines the structural properties of binary and tertiary mixtures made of the cold-setting biopolymers agarose and gelatin and a lipid phase with solid or liquid-like viscoelasticity. The working protocol included the techniques of small-deformation dynamic oscillation on shear, modulated differential scanning calorimetry and scanning electron microscopy, and theoretical modeling that adapted ideas of relating the morphology to the elastic modulus of synthetic polyblends and block polymers. The experimental setting was designed to encourage extensive phase separation in the binary gel of agarose and gelatin whose mechanical properties were rationalized on the basis of a bicontinuous blending law. The presence of two continuous phases allowed the slower-gelling component (gelatin) to exhibit favorable relative affinity for the solvent with increasing concentrations of the protein in the system. This is an unexpected outcome that contradicts the central finding of a single value of the p factor observed in the distribution of solvent between the continuous matrix and discontinuous inclusions of deswelled binary gels reported earlier in the literature. The incorporation of a lipid phase of effectively zero elastic modulus or in excess of 10(8) Pa in the composite aqueous gel weakens or reinforces the matrix accordingly. The elastic moduli and morphology of the tertiary blend were related to changing the relative phase volumes of components using analytical expressions of isotropically dispersed soft or rigid filler particles in a polymeric matrix.