Purification and some properties of .ALPHA.-amylases from polished rice granules.

Sakamoto, Kaoru; Maruyama, Etsuko

doi:10.5458/jag1972.37.29

Cited by 7 publications

(4 citation statements)

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“…One is that a greater amount of free sugars was already present in the rice grains. The other is that the early-harvest rice had higher amounts of starch degradation enzymes than the ordinary-harvest rice, so that the starch was hydrolyzed in the process of soaking and cooking of the grains, generating the additional free sugars (Sakamoto & Maruyama, 1990;Tajima et al, 1992;Tajima et al, 1994). To confirm this possibility, the amount of free sugars in the grains of both groups (not cooked rice) was determined in the presence or absence of mercuric chloride, which completely inhibits starch degradation enzyme activity.…”

Section: Sensory Test and Related Sensory Characters Of The Cooked Eamentioning

confidence: 99%

Effects of Early Harvesting of Grains on Taste Characteristics of Cooked Rice.

Arai¹,

Itani²

2000

FSTR

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In order to clarify the effects of early harvesting of rice grains on the taste characteristics of cooked rice, especially on the taste items of "sweetness" and "deliciousness," we compared "early-harvest" rice which was harvested 10 days before the ordinary harvest time and "ordinary-harvest" rice which was harvested at the usual time. From the results of sensory tests, the cooked early-harvest rice was evaluated as being sweeter and more delicious than the cooked ordinary-harvest rice. The greater sweetness in the former rice was primarily due to the formation of glucose, maltose and maltoligosaccharides from starch, probably by starch degradation enzymes during soaking and/or cooking. The cooked early-harvest rice also contained more L-glutamic acid than the cooked ordinary-harvest rice. From these results, it was concluded that when rice is harvested 10 days before the ordinary time of harvesting, the cooked rice will be sweeter and more delicious.Keywords: early harvesting, cooked rice, sweetness, maltoligosaccharides, starch degradation enzymeThe time of harvesting rice grains has conventionally been determined from the standpoints of attaining a good external appearance, getting sufficient yield and making the harvesting work easier, without taking the eating quality of the harvested grains into account. On the other hand, when the harvesting time of rice has been extremely retarded or advanced the taste of cooked rice has been reduced; suggesting that the time of harvest of the grains can have a critical influence on the quality of cooked rice. To identify an optimum harvesting time to assure rice of good eating quality, many studies have examined factors related to taste such as the contents of amylose and protein in milled rice (Taira et al., 1978;Asaoka et al., 1985;Tamaki et al., 1989a;Matsue et al. 1991;Takebe et al., 1994) and the texture parameters of cooked rice (Ebata et al., 1982;Tamaki et al., 1989a) in relation to the time of harvesting. It has been asserted in these studies that an adequate period of time for harvesting rice grains to obtain cooked rice of good quality is about 40 days after heading (Ebata et al., 1982).More, recent reports showed that in addition to such taste components as amylose and protein, other characteristics of sweetness and deliciousness greatly contribute to the quality of cooked rice (Tamaki et al., 1989b;Matsuzaki et al., 1992;Sugiyama et al., 1995;Arai et al., 1997). However, the optimum time for harvesting grains with special reference to the taste characteristics of cooked rice has scarcely been examined to date.The objective of the present study was thus to clarify the effects, which the harvest time, especially early harvest, has on these previously unevaluated taste characteristics of cooked rice, as well as on taste characters, which have already been subjected to research. Materials and MethodsPlant materials Rice plants (Oryza sativa L. cv. Koshihikari) grown at Nita-cho in Shimane Prefecture in 1997 were used. Developing grains were sampled at 32 and 4...

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Section: Sensory Test and Related Sensory Characters Of The Cooked Eamentioning

confidence: 99%

Effects of Early Harvesting of Grains on Taste Characteristics of Cooked Rice.

Arai¹,

Itani²

2000

FSTR

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“…Isozyme IV may be the isoform of α-amylase in milled rice. Nanjo (2004) isolated and identified 10 α-amylase isoforms from germinating rice, and Sakamoto and Maruyama (1990) purified α-amylase from milled rice. Isozyme III may be the β-amylase purified from milled rice by Maruyama (1981).…”

Section: Discussionmentioning

confidence: 99%

Presence and Activity of Various Amylases in Rice: Effect on Texture and Leached Sugar Composition during Cooking

Tsujii¹,

Nagafuku

Miyake

et al. 2013

FSTR

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Amylase isozymes from non-glutinous japonica and indica rice types showed various band patterns, strengths and intensities based on zymography. Major bands were presumed to be α-and β-amylase according to their molecular weights; other amylases, 270 and 200 kDa in size, were also detected. Three debranching enzymes (DBEs) were detected from the dye pattern as well. Amylase activities were observed at pH 7.0 during rice cooking. However, the α-amylase activity at pH 7.0 was 50% lower than that at pH 5.0; DBE, β-amylase, and α-glucosidase values were similarly reduced by 25%, 90% and 99%, respectively. α-Amylase activity and DBE activities correlated positively with both the amount of maltooligomer leached during rice cooking and the adhesiveness of cooked rice. Thus, it is considered that the activity of amylase isozymes affects the palatability of cooked rice. Therefore, enzymes from rice endosperm may represent a new and highly useful biomarker for evaluating the palatability of cooked rice.

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“…Most endogenous enzymes of starch or protein degradation purified from rice seeds have their optimum pH around pH 4-5 or pH 3-6, respectively (Asakura et al, 1997;Iwata et al, 2003;Kato & Minamikawa, 1996;Sakamoto & Maruyama, 1990;Doi, Shibata et al, 1980). In this study, hydrolytic activities of oligosaccharides and proteolytic activities enhanced at pH 5 (Figs.…”

Section: Effects Of Acidic Ph On Chemical Components Of Cooked Ricementioning

confidence: 88%

Characterization of endogenous enzymes of milled rice and its application to rice cooking

Mabashi¹,

Ookura²,

Tominaga³

et al. 2009

Food Research International

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Purification and some properties of .ALPHA.-amylases from polished rice granules.

Cited by 7 publications

References 0 publications

Effects of Early Harvesting of Grains on Taste Characteristics of Cooked Rice.

Effects of Early Harvesting of Grains on Taste Characteristics of Cooked Rice.

Presence and Activity of Various Amylases in Rice: Effect on Texture and Leached Sugar Composition during Cooking

Characterization of endogenous enzymes of milled rice and its application to rice cooking

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