Potato starch is characterized by discernibly high content of starch-bound phosphate monoester groups, and metal cations are attached to the phosphate groups by ion forces. A high level of divalent cations appears to lead to good viscosity stability of potato starch by ionically cross-linking starch phosphate esters. However, potato starches manufactured in factories in Hokkaido, the northernmost island of Japan, do not show good viscosity stability due to high potassium content and low divalent cation content. To overcome this, potato starches substituted with divalent cations, such as calcium, magnesium, and iron, have been produced by treating potato starches with solutions containing divalent cations. This review paper provides an overview of the preparation methods and physicochemical properties of divalent cation–substituted potato starch. Moreover, food applications of divalent cation–substituted potato starch are also discussed.

Resistant starch (RS) displays physiological properties similar to that of dietary fiber. In this study, the physical properties and palatability of bread made with RS type 4 (RS-4, chemically modified starch) were evaluated. Distarch phosphate potato starch, distarch phosphate rice starch, distarch phosphate tapioca starch, phosphated distarch phosphate sweet potato starch, and phosphated distarch phosphate wheat starch were the sources. Wheat flour was replaced with 20% (w/w) RS-4, and the bread was thereby considered as RS-4 added bread. Bread without RS-4 was the control bread. RS-4 added loaves of bread had less specific volume than the control bread. The hardness of RS-4 added bread samples was also higher than that of the control bread. It was observed using a scanning electron microscope (SEM) that RS-4 was not gelatinized in bread. However, RS-4 added bread samples obtained overall acceptability comparable to that of the control bread in the sensory evaluation. It was concluded that differences in the sizes of starch particles added to the bread did not affect palatability. The RS-4 bread with potatoes starch appeared to cause the hardness of the crumb during baking; suggesting that RS-4 derived from cereals would be more suitable for use in bread.

In this study, we aimed to elucidate the optimal conditions for baking gluten-free rice bread while considering the powder characteristics of 10 rice flour varieties by optimizing the quantity of water to be added and examining the effects of particle size, protein content, amylose content, and degree of starch damage in rice flour.

Rice breads were prepared with varying quantities of water, and the range of quantity of water that allowed baking varied depending on the variety of rice flour used. We determined that high protein content in rice flour allowed a wide range of quantity of water that can be added to be suitable for bread baking; however, concurrent with this are that the compressive stress of the bread increases as well. Moreover, we examined the effect of ingredient composition on the optimal quantity of water added to ensure the swelling of the rice flour bread and found that the quantity of water that can be added ranged from 15- to 17-fold when the quantity of water to be added was based on the protein content in rice flour. These results indicate that when preparing gluten-free rice bread with a large specific volume, the quantity of water to be added can be determined using the protein content in rice flour as an indicator. Additionally, we found that when the protein content in rice flour is not known, the quantity of water to be added can be adjusted to achieve 10 to 20 Pa loss modulus G’’ of the batter.

This paper reviews starch gel foods from the perspective of cookery science: warabi mochi (traditional sweet gel in Japan) and blancmange as hard gels and pastry cream/custard as a soft gel. Since warabi mochi is made from expensive warabi starch, physiochemical properties of several starches were tested as possible replacers. High potential of sago starch as a replacer was demonstrated as compared with sweet potato, potato, tapioca, and kudzu starches which are currently used as the replacers. Sago starch showed excellent characteristics in gel elasticity comparable to sweet potato and potato starches, high gel cohesiveness and low gel adhesiveness comparable to tapioca starch, and gel hardness comparable to kudzu starch. Toward quality improvements of warabi mochi, its preparation methods were also optimized. For instance, trehalose was added to suppress starch retrogradation in warabi mochi, and modified wheat starch was added to stabilize its gel quality. Meanwhile, warabi mochi is primarily a mixture of starches, sugars, and water, whereas most starch gel foods are mixtures of the primary ingredients and secondary ingredients such as proteins and fats. As for the blancmange, milk was replaced with soy protein isolate or soy milk powder for its quality improvement. For maximizing the physicochemical properties as well as taste, ratio of starch, protein, and fat was optimized by Scheffé’s simplex lattice design method: its triangular diagram clearly showed its optimal ratio for blancmange of high quality. Regarding pastry cream/custard, since its melting mouthfeel governs overall quality preference, methods to evaluate the melting mouthfeel were established. Thereafter, applicability of modified starches to pastry cream/custard was investigated to fit its texture to each food preparation. Based on physicochemical properties of the modified starches, pastry cream/custard preparation was adjusted to each of various food products.