A novel starch: Characterizations of starches separated from tea (Camellia sinensis (L.) O. Ktze) seed

Changes of crystalline structure and physicochemical properties of Pueraria lobata var. thomsonii starch under water deficit

Crystal type is an important physicochemical property of starch. However, it is currently unclear whether changes in crystal type affect other properties of starch. This study discovered that water deficit resulted in an increase in small starch granules and transparency in Pueraria lobata var. thomsonii, while causing a decrease in amylose content and swelling power. Additionally, the crystal type of P. Thomsonii starch changed from CB-type to CA-type under water deficit, without significantly altering the short-range ordered structure and chain length distribution of starch. This transformation in crystal type led to peak splitting in the DSC heat flow curve of starch, alterations in gelatinization behavior, and an increase in resistant starch content. These changes in crystalline structure and physicochemical properties of starch granules are considered as adaptive strategies employed by P. Thomsonii to cope with water deficit.

Physicochemical characteristics of tea seed starches from twenty-five cultivars

The physicochemical features of starches separated from tea seeds of 25 cultivars were analyzed. The distinct characteristic of tea seed starches was that they had high apparent amylose content (AAC, 28.94-39.91 %) and resistant starch contents (4.64-8.24 %), suggesting that tea starch can be used for production of low glycemic index food. One cultivar (T12) had smallest breakdown (74.2 RVU) and highest gel hardness, indicating it performed stably during shear thinning, resulting in a firm texture. Another cultivar (T25) had a peak viscosity of 417.6 RVU, a large breakdown and small setback, suggesting a low tendency for retrogradation. There was a range of 61.6 °C to 77.5 °C for the peak gelatinization temperature and 0.163 to 0.390 for the flow behavior index values. These parameters could serve for selecting suitable starches with minor differences in physicochemical properties for food use. Correlation analysis indicated that AAC is a key factor determining starch retrogradation properties. The broad genetic diversity in the tea seed starch physicochemical features provided potentially versatile applications in the food industry. The results gained from the present study contribute to a better understanding of tea seed starch quality, and encourage its application in many value-added food products.

Physicochemical characterizations of five Dioscorea alata L. starches from China

D. alata is an important edible and medicinal plant in China. Its tuber is rich in starch but the understanding of the physiochemical properties of D. alata starch is limited. In order to explore the processing and application potential of different D. alata accessions in China, five kinds of D. alata starch (LY, WC, XT, GZ, SM) were isolated and characterized. The study showed that D. alata tubers contained abundant starch, enriched in amylose and resistant starch (RS). D. alata starches showed B-type or C-type diffraction pattern, had higher RS content and gelatinization temperature (GT), lower fa and viscosity when compared to D. opposita, D. esculenta, and D. nipponica. Among D. alata starches, D. alata (SM) showing the C-type diffraction pattern, had the lowest proportion of fa with 10.48 %, the highest amylose, RS2 and RS3 content of 40.24 %, 84.17 % and 10.48 % respectively, and the highest GT and viscosity. The results indicated that D. alata tubers are potential sources for novel starch with high amylose and RS content, and provided a theoretical basis for further utilizations of D. alata starch in food processing and industry application.

Nonconventional Hydrocolloids’ Technological and Functional Potential for Food Applications

This review aims to study the alternatives to conventional industrial starches, describing uncommon sources along with their technological characteristics, processing, and performance on food products. Minor components remaining after extraction play an important role in starch performance despite their low percentage, as happens with tuber starches, where minerals may affect gelatinization. This feature can be leveraged in favor of the different needs of the food industry, with diversified applications in the market being considered in the manufacture of both plant and animal-based products with different sensory attributes. Hydrocolloids, different from starch, may also modify the technological outcome of the amylaceous fraction; therefore, combinations should be considered, as advantages and disadvantages linked to biological origin, consumer perception, or technological performance may arise. Among water-based system modifiers, starches and nonstarch hydrocolloids are particularly interesting, as their use reaches millions of sales in a multiplicity of specialties, including nonfood businesses, and could promote a diversified scheme that may address current monocrop production drawbacks for the future sustainability of the food system.