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Lu S.,China Grain Products Research and Development Institute | Lu S.,National Chung Hsing University | Cik T.-T.,National Chung Hsing University | Lii C.-Y.,Academia Sinica, Taiwan | And 2 more authors.
LWT - Food Science and Technology | Year: 2013

The susceptibility of cooked rice to α-amylolysis were studied in four Taiwanese rice cultivars differing in amylose contents, i.e. Taichung Native 1(TCN1, indica), Taigung 9 (TG9, japonica), Taichung Sen Waxy 1 (TCSW1, indica waxy), and Taichung Waxy 70 (TCW70, japonica waxy). In addition, the correlation between α-amylolysis and the microstructure and textural properties of the four rice cultivars was investigated. The hardness, gumminess and chewiness of cooked rice followed the order of TCN1>TG9>TCS>t;TCW70. However the waxy rice cultivars showed a higher extent and rate of α-amylolysis. Using scanning electron microscopy, the microstructure revealed that the low-amylose rice and waxy rice cultivars contained hollow in the central endosperm. The internal hollow disappeared after α-amylolysis, indicating that α-amylase had penetrated the cooked grain, resulting in the inside-out hydrolysis. These results indicated that the textural properties of cooked rice are influenced mainly by its amylose/amylopectin ratio, followed by influencing the pattern of α-amylolysis. © 2013 Elsevier Ltd.


Lin M.-H.A.,National Pingtung University of Science and Technology | Wu M.-C.,National Pingtung University of Science and Technology | Lu S.,China Grain Products Research and Development Institute | Lin J.,National Pingtung University of Science and Technology
World Journal of Gastroenterology | Year: 2010

AIM: To determine the glycemic index (GI), glycemic load (GL) and insulinemic index (II) of five starchy foods that are commonly used in Chinese diets. METHODS: Ten healthy subjects aged between 20-30 years were recruited. Each subject was asked to consume 50 g of available carbohydrate portions of test foods and reference food. Finger capillary blood samples were collected at the start of eating and 15, 30, 45, 60, 90 and 120 min after consumption. The GI and II of foods were calculated from the ratio of incremental area under the glucose/insulin response curves of test and reference foods. The GL for each test food was determined from its GI value and carbohydrate content. RESULTS: The results showed that brown rice elicited the highest postprandial glucose and insulin responses, followed by taro, adlay, yam and mung bean noodles, which produced the lowest. Among the five starchy foods, brown rice evoked the highest GI and GL at 82 ± 0.2 and 18 ± 0.2, followed by taro (69 ± 0.4, 12 ± 0.2), adlay (55 ± 0.4, 10 ± 0.2), yam (52 ± 0.3, 9 ± 0.0) and mung bean noodles (28 ± 0.5, 7 ± 0.2), respectively. The II values of the test foods corresponded with GI values. Similarly, brown rice gave the highest II at 81 ± 0.1, followed by taro (73 ± 0.3), adlay (67 ± 0.3), yam (64 ± 0.5) and mung bean noodles (38 ± 0.3). All five starchy foods had lower GI, GL and II than reference bread (P < 0.05). CONCLUSION: The GI, GL and II values of starchy foods provide important information for the public to manage their diet and could be useful for the prevention of lifestyle-related diseases such as diabetes mellitus. © 2010 Baishideng.


Lu S.,China Grain Products Research and Development Institute | Lu S.,National Chung Hsing University | Chen J.-J.,Academia Sinica, Taiwan | Chen Y.-K.,National Chung Hsing University | And 3 more authors.
Journal of Cereal Science | Year: 2011

Three rice starches from indica (TNuS19), japonica (TNu67) and waxy (TCW70) were used as samples to investigate the water mobility, viscoelasticity and textural properties of starch gels using pulsed nuclear magnetic resonance (PNMR), dynamic rheometer and texture analyzer. The spin-spin relaxation time (T2), showed water mobility of starch gels was detected with starch concentrations 10-30%. Generally, the TNuS19 and TNu67 at ≥20% showed two components (T2a and T2b) in water mobility, where T2a and T2b related to solid-like and liquid-like water molecules in starch gels, respectively. However, the TCW70 over the concentrations examined had only T2b component, higher than those of corresponding TNuS19 and TNu67. The storage (G') and loss (G″) moduli of starch gels were in the order of TNuS19 > TNu67 > TCW70. Texture analyzer analysis indicated that TNuS19 had higher hardness, stickiness and adhesiveness than did the TNu67 and TCW70, and changed significantly with the starch concentration increase. The value of T2b was highly correlated with physical properties of starch gels, especially with dynamic rheological parameters. It is suggested that amylose content may play a major role to influence the water mobility of starch gels which affects the specific viscoelasticity and textural properties of starch gels. © 2010 Elsevier Ltd.


Lai P.,Providence University | Li K.Y.,Tunghai University | Lu S.,China Grain Products Research and Development Institute | Chen H.H.,National Penghu University of Science and Technology
Food Chemistry | Year: 2011

Various dietary fibres (DF) from rice flours of Taichung Sen 10 (TCS10) and Tainung 67 (TNu67) rice cultivars were isolated while their roles in governing the pasting and the rheological properties of the rice starch were examined. The addition of DF (at 5 wt.% on dry starch basis), most notably from TCS10 cultivar generally caused significant increases in swelling power and pasting viscosities of 10 wt.% rice starch dispersions. Furthermore, the addition of DF was found to improve the rheological parameters of the 10 wt.% rice starch gel. Nuclear magnetic resonance (NMR) relaxation measurements revealed that the water mobility of starch gel was decreased with the addition of DF. The statistically significant factors were concluded to be arabinoxylan-related compositions for the increments of pasting and rheological characteristics, meanwhile the swelling power and setback viscosity mainly depend on β-glucan compositions and arabinose-to-xylose molar ratio (RAX). © 2011 Elsevier Ltd. All rights reserved.


Hsu R.J.C.,National Taiwan University of Science and Technology | Hsu R.J.C.,China Grain Products Research and Development Institute | Chen H.-J.,National Taiwan University of Science and Technology | Lu S.,China Grain Products Research and Development Institute | Chiang W.,National Taiwan University of Science and Technology
Journal of Cereal Science | Year: 2015

Instant rice has become increasingly popular due to its convenience. Reducing the starch digestibility of instant rice may increase its potential health benefits. The aims of this study were to define the optimum conditions for cooking, retrogradation and drying to reduce the in vitro starch digestibility of instant rice. Three varieties of rice from Taiwan (low-amylose japonica [Taikeng 9], low-amylose indica [Taichung Sen 10] and high-amylose indica [Taichung Sen 17]) were prepared using different cooking conditions and durations of retrogradation. Starch digestibility was determined by analyzing the amount of rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) in the instant rice. Cooking at 86 °C for 28 min in a 1.0-fold volume of water significantly reduced RDS and increased SDS compared to rice cooked on a traditional electronic cooker. The combination of retrogradation and low-temperature drying significantly reduced the RDS of instant rice after rehydration. A reduction in RDS was accompanied by an increase in SDS and RS in low-amylose japonica rice, increased RS in low-amylose indica rice, and reduced SDS and increased RS in high-amylose rice. Optimizing cooking methods and retrogradation reduced the starch digestibility of instant rice; this may help improve its healthful qualities. © 2015 Elsevier Ltd.


Lin S.-Y.,Chinese Culture University | Chen H.-H.,National Penghu University of Science and Technology | Lu S.,China Grain Products Research and Development Institute | Wang P.-C.,Chinese Culture University
Journal of Texture Studies | Year: 2012

Steamed bread is a fermented wheat flour product that is cooked by being steamed in a steamer. The properties of dough and the quality of steamed bread incorporated with barley flour at 10, 20 and 30% substitution levels are investigated. Increasing levels of barley flour correspondingly decreases the gluten content and increases the β-glucan content. Upon incorporation of barley flour, the dough development time, departure time and stability time are decreased, but the mixing tolerance index is increased. The incorporation of barley flour into wheat flour also significantly decreases the extensibility, increases the value of R/E ratio and decreases the value of work input. In addition, increased levels of barley flour cause significant decreases in the specific volume, brightness and whiteness index of steamed bread, as well as increases in hardness and chewiness. This study also shows that six-row barley pearl flour contains more dietary fiber and has a more favorable influence than barley endosperm flour. © 2012 Wiley Periodicals, Inc..


Hsu R.J.-C.,National Taiwan University of Science and Technology | Hsu R.J.-C.,China Grain Products Research and Development Institute | Lu S.,China Grain Products Research and Development Institute | Chang Y.-H.,Providence University | Chiang W.,National Taiwan University of Science and Technology
Journal of Cereal Science | Year: 2015

Flours derived from rice varieties with different amylose content possess distinct physicochemical and molecular properties. The aim of this study was to determine optimal processing conditions for preparing rice flour-based foods with reduced starch digestibility. To do so, we evaluated the invitro starch digestibility of rice flours with five varieties. Reducing the amount of water (from 10-fold to 4-fold of rice flour) used for cooking rice flour lowered its starch digestibility, and the magnitude of the decrease was positively correlated with amylose content. When retrogradation of cooked rice flour proceeded for 7 days, the digestibility of high-amylose rice flours declined rapidly in the first 3 days, whereas the digestibility of low-amylose rice flours declined continuously. Our analysis also demonstrated that the chain length distribution of starch molecules and the final and setback viscosity pasting properties were the most important parameters affecting the digestibility of rice flours. Based on our results, it appears possible to reduce rice starch digestibility by establishing optimum processing conditions for different varieties. We suggest a 7-fold addition of water and retrogradation for 1 day for high-amylose rice varieties and a 4-fold addition of water with 3 days of retrogradation for low-amylose rice. © 2014.

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