Factors influencing the physico-chemical, morphological, thermal and rheological properties of some chemically modified starches for food applications--A review

Microwave food processing—A review

Octenyl succinic anhydride (OSA) modified early indica rice starch was prepared in aqueous slurry systems and the major factors affecting the esterification were investigated systematically. The physicochemical properties of the products were determined by means of Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction and Rapid Visco Analyser (RVA). The results indicated that the suitable parameters for the preparation of OSA starch from early indica rice starch in aqueous slurry systems were as follows: concentration of starch slurry 35% (in proportion to water, w/w), reaction period 4 h, pH of reaction system 8.5, reaction temperature 35°C, amount of OSA 3% (in proportion to starch, w/w). The degree of substitution (DS) was 0 018 and the reaction efficiency (RE) was 78%. FT-IR spectroscopy showed characteristic absorption of the ester carbonyl groups in the OSA starch at 1724 cm -1 . SEM and X-ray diffraction revealed that OSA groups acted by first attacking the surface and some pores formed, but OSA modification caused no change in the crystalline pattern of rice starch up to DS 0.046. RVA results indicated that the starch derivatives gelatinized at shorter time to achieve higher viscosities with increased OSA modification.

Preparation and Properties of Octenyl Succinic Anhydride Modified Early Indica Rice Starch

Preparation and properties of octenyl succinic anhydride modified potato starch

Canola Council of Canada, Winnipeg, Manitoba, Canada The rising costs of nonrenewable feedstocks and environmental concerns with their industrial usage have encouraged the study and development of renewable products, including thermoplastic starch (TPS). Starch is an abundant, plant-based biodegradable material with interesting physicochemical characteristics that can be exploited, and this has received attention for development of TPS products. Starch exhibits usable thermoplastic properties when plasticizers, elevated temperatures, and shear are present. The choice of plasticizer has an effect on TPS, even when these have similar plasticization principles. Most TPS have glass transition temperature, Tg, in the range of approximately -75 to 10°C. Glassy transition of TPS is detected by differential scanning calorimeter (DSC) and thermodynamic analyzer (DMA), although DMA has been found to be more sensitive and effective. TPS has low tensile properties, typically below 6 MPa in tensile strength (TS). The addition of synthetic polymers, nanoclay, and fiber can improve TS and water-resistance ability. The moisture sorption behavior of TPS is described in GAB and BET models, from which monolayer moisture content and specific area are derived. Current studies on surface tension, gas permeability, crystallinity, and so on of the TPS are also reviewed.

Thermoplastic Starch Processing and Characteristics—A Review

Commercial rice starch, in aqueous slurry (42% starch solids), was acetylated with 6.3% acetic anhydride (on a dry starch basis). The acetylated starch showed lower (P < 0.05) moisture, ash, crude protein, and apparent amylose content and pH than native starch. The crude fat and fiber, absolute density and titratable acidity were the same (P ≥ 0.05) in both starches. The percentage of acetyl groups and degree of substitution were 0.67% and 0.03, respectively. These groups caused an increase in water absorption, swelling power and solubility, which also affected the initial pasting temperature, viscosity at 90 °C, viscosity at 50 °C and setback; the acetylated starch showed a lower initial pasting temperature and setback than native starch, while both viscosity values increased. The morphology of acetylated rice starch was slightly modified.

Effect of Acetylation on Some Properties of Rice Starch

Evaluation of lentil starches modified by microwave irradiation and extrusion cooking

In this study a comparison between the chemical composition and physical characteristics of sagu (Canna edulis Kerr) and zulu (Maranta sp.) rhizomes was made. The rheological properties and morphometric characteristics of starches isolated from both modified underground stems were also compared. Sagu rhizomes are bigger than those of zulu. Their external appearance resembles that of yam. The zulu rhizomes yield larger quantities of edible pulps because of the lower percent of peel. The results of the chemical composition analysis show that sagu rhizomes have more total carbohydrate content and less crude proteins, fat, and fiber than zulu rhizomes. Keywords: Sagu rhizomes; zulu rhizomes; Canna rhizomes; Maranta rhizomes; starch; SEM observation

Some Characteristics of Sagu (Canna edulis Kerr) and Zulu (Maranta sp.) Rhizomes

Starch isolated from two varieties of sorghum; white and dark grain, have been examined and compared for chemical, physical, physicochemical and rheological properties. Additionally, this study tested starch isolation laboratory scale method for dark sorghum grain. The levels of crude protein, crude fat and ash contents were lower in white sorghum than in dark sorghum starch. No difference was observed between apparent amylose content in both starches. The physicochemical and rheological behavior reveals differences in functional properties and it can be attributed to isolation procedures.

Characterization of starch isolated from white and dark sorghum

SUMMARY The aim of this study was to produce flours from the edible portion of cassava (Manihot esculenta Crantz) roots, treat them by heat in different forms (normal and pressure cooking, in limited and excess water conditions, and in the presence or absence of NaCl) and characterize them in their chemical composition, physical and functional properties. The flour preparation procedure affected both the chemical composition and gelatinization profile. The control (raw flour) and heat-treated samples displayed a set-back reduction. Pregelatinized flours showed de creased consistency and absorption indices, and augmented departure time, stability, tolerance index and time to breakdown values, as compared to control sample. These flours are sug gested as potential ingredients in new or conventional product development.

Zurima González

Papers

Effect of Acetylation on Some Properties of Rice Starch

Evaluation of lentil starches modified by microwave irradiation and extrusion cooking

Some Characteristics of Sagu (Canna edulis Kerr) and Zulu (Maranta sp.) Rhizomes

Characterization of starch isolated from white and dark sorghum

Production and characterization of cassava (Manihot esculenta Crantz) flours using different thermal Treatments