Takahiro Noda

Mixed Biopolymer Systems Based on Starch

A binary mixture of starch–starch or starch with other biopolymers such as protein and non-starch polysaccharides could provide a new approach in producing starch-based food products. In the context of food processing, a specific adjustment in the rheological properties plays an important role in regulating production processing and optimizing the applicability, stability, and sensory of the final food products. This review examines various biopolymer mixtures based on starch and the influence of their interaction on physicochemical and rheological properties of the starch-based foods. It is evident that the physicochemical and rheological characteristics of the biopolymers mixture are highly dependent on the type of starch and other biopolymers that make them up mixing ratios, mixing procedure and presence of other food ingredients in the mixture. Understanding these properties will lead to improve the formulation of starch–based foods and minimize the need to resort to chemically modified starch.

Acute and Subacute Toxicity Studies on Rutin-Rich Tartary Buckwheat Dough in Experimental Animals

In order to investigate the toxicity of rutin-rich dough from the Tartary buckwheat variety Manten-Kirari, acute and subacute toxicity studies (10,000 and 5,000 mg/kg flour, respectively) were performed using rats. In the acute toxicity study, no toxic symptoms were observed and no rats died during the test. Body weight in the Manten-Kirari-treated group was not significantly different when compared with that of the control group. On pathologico-anatomic observation, no unusual symptoms were observed in the Manten-Kirari-treated group when compared with the control group. In the subacute toxicity study, no toxic symptoms were observed and no rats died during the test. Body weight and food intake in the Manten-Kirari-treated and common buckwheat groups were not significantly different when compared with the control group. However, some investigated properties, such as urine protein and serum albumin, were significantly different in the Manten-Kirari and common buckwheat groups when compared with the control group. However, these changes were not caused by toxicity, but by transient changes. On pathologico-anatomic observation, some abnormalities were observed in the liver, kidneys, heart, lung, bronchi and pituitary gland in some rats. However, the incidental rates in the Manten-Kirari and common buckwheat groups did not differ when compared to controls. Therefore, these abnormalities may be caused by natural generation. Based on these results, we concluded that dough at a dose of 5,000 mg flour/kg is at a non effect level.

Effect of some biopolymers on the rheological behavior of surimi gel

The objective of this study was to investigate the effect of selected biopolymers on the rheological properties of surimi. In our paper, we highlight the functional properties and rheological aspects of some starch mixtures used in surimi. However, the influence of some other ingredients, such as cryoprotectants, mannans, and hydroxylpropylmethylcellulose (HPMC), on the rheological properties of surimi is also described. The outcome reveals that storage modulus increased with the addition of higher levels of starch. Moreover, the increasing starch level increased the breaking force, deformation, and gel strength of surimi as a result of the absorption of water by starch granules in the mixture to make the surimi more rigid. On the other hand, the addition of cryoprotectants, mannans, and HPMC improved the rheological properties of surimi. The data obtained in this paper could be beneficial particularly to the scientists who deal with food processing field.

Traits of shattering resistant buckwheat ‘W/SK86GF’

Seed shattering is a significant problem with buckwheat, especially at harvesting time. Several reports have shown that a green-flower mutant of buckwheat, such as W/SK86GF, has a strong pedicel. Although a strong pedicel may provide some resistance to shattering in the field, no study has thoroughly examined this issue. In this paper, we demonstrate that a W/SK86GF has shattering resistance by comparing the degrees of shattering of W/SK86GF and Kitawasesoba (leading variety of Hokkaido with non-green-flower traits) through a test for four years, including a typhoon hit year in the field. In a non-typhoon year, the shattering seed ratio (shattering seed weight/(yield + shattering seed weight) × 100) of W/SK86GF at maturing time +15 days (+15D) was lower than that of Kitawasesoba. In a typhoon hit year, the shattering seed ratios of Kitawasesoba at maturing time and +15D were surprisingly high, 14.4 and 21.1%, respectively. On the other hand, those of W/SK86GF were only 3.08% and 2.57%, respectively; indicating W/SK86GF is promising as a shattering resistant line even in a typhoon hit year. From these results, shattering resistance of W/SK86GF can be evaluated after maturing time such as +15D and pedicel strength would confer W/SK86GF a shattering resistant trait.

Preparation of calcium- and magnesium-fortified potato starches with altered pasting properties.

Calcium- and magnesium-fortified potato starches were prepared by immersion in various concentrations of CaCl2 and MgCl2 aqueous solutions, respectively. The pasting properties, i.e., peak viscosity and breakdown, of all the starches obtained above were analyzed using a Rapid Visco Analyzer. Furthermore, the gelatinization properties and in vitro digestibility of the representative calcium- and magnesium-fortified starches were tested. The maximum calcium content of the fortified potato starches was as high as 686 ppm with the addition of a high-concentration CaCl2 solution, while the calcium content of the control potato starch was 99 ppm. The magnesium content increased from 89 to 421 ppm by treatment of the potato starch with an MgCl2 solution. Markedly lower values of peak viscosity and breakdown were observed in calcium- and magnesium-fortified potato starches than in the control potato starch. However, the gelatinization temperature and enthalpy as well as resistant starch content of calcium- and magnesium-fortified potato starches were similar to those of the control potato starch. It is concluded that potato starches with altered pasting properties can be easily manufactured by the use of solutions containing high levels of calcium and magnesium.

Factors Influencing Starch Digestibility

Starch that avoids digestion by amylases in the small intestine and passes to the large bowel for fermentation is defined as resistant starch (RS). RS appears to be desirable in human health, as it has functional properties similar to fermentable dietary fibers. The amount of RS is related to the rate of starch digestion by amylases. Enzymatic digestibility of starch is largely dependent on physicochemical properties of the starch. Enzymatic digestibility of gelatinized and raw starch is an important property in food manufacture. In potato starch, raw starch granules have larger granule size, which is highly resistant to hydrolysis by amylase. In addition, potato starch has a definitely higher amount of covalently bound phosphate compared to other starches. In this study, enzymatic digestibility of raw and gelatinized starches in various potato starches besides sweet potato, cassava, and yam starches was determined along with other starch properties, median granule size, phosphorus content, and pasting properties. Furthermore, the correlation coefficients were calculated between the enzymatic digestibility and other starch quality parameters. A larger granule size was closely associated with a lower digestibility in raw starch, while the digestibility in gelatinized starch did not correlate with the median granule size. An increase in the phosphorus content resulted in a definitely lower digestibility in raw starch and tended to decrease the digestibility in gelatinized starch for the composite of potato and other starches.