• The Korean Journal of Food And Nutrition
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• v.9 no.1
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• pp.37-44
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• 1996

Korean traditional Sikhye is made from rice and malt. Since 1740, there have been many records about the method of making traditional Sikhye, generally used in the folks. And the first records of sugar addition Sikhye were found In 1924. Therefore commercial sugar Sikhye is not traditional. Traditional Sikhye uses 30% of rice and malt (dry weight) as raw material, and main content is maltose. However commercial Sikhye uses only 3% of cooked rice, and adds 10% of sugar, .Even though some domestic Sikhye used sugar, the amount of added sugar does not exceed 115 of raw materials. Therefore, commercial Sikhye differs from not only traditional Sikhye but also domestic sugar Sikhye.

• Journal of Ginseng Research
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• v.31 no.4
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• pp.191-195
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• 2007

Red ginseng sikhye is one of Korean unique beverages with the addition of effective ingredients of ginseng. Considering economical and mechanical efficiency and quality of sikhye, the optimum conditions for saccharification is to saccharify at 90 degree celsius for 3 hours in the composition of 4% of malt, 20% of steamed rice, and 6% of red ginseng power. The red ginseng sikhye has high soluble solid content over 33% compared with conventional commercial sikhye. On the other hand, ginseng sikhye, which shows low pH, has more or less higher acidity than conventional commercial one. Especially the turbidity of the red ginseng sikhye is much higher than that of commercial sikhye, due to as high amount of rice as 20% compared with 3% in the commercial one. The use of high quantity of rice affected the level of turbidity in red ginseng sikhye. In this study, we wanted to establish optimum conditions for saccharification in manufacturing red ginseng sikhye which contains effective herbal medicinal ingredients maintaining the original taste of traditional sikhye.

• The Korean Journal of Food And Nutrition
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• v.9 no.1
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• pp.45-51
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• 1996

Korean traditional Sikhye is made from rice and malt, and It's main product Is maltose. However commercial Sikhye differs from traditional Sikhye because it's main component is sucrose. Sikhye industry faces many problems such as contamination of malt with microorganisms, low amylase activity of malt and technical difficulties. There is no commercial Sikhye which is only using rice and malt by these reasons. To produce the traditional Sikhye free from these problems, it is necessary to restrict the microorganisms of malt and to standardize the amylase activity of malt. In addition, the Introduction of effective control and sanitaric process is required. In Sikhye production. if $\beta$-amylase and isoamylase or pullulanase were added, starch could be saccharified 100% as maltose. Accordingly, this method brings us the low cost of Sikhye.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.92-96
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• 1997

A Korean commercial sweet rice drink "Sikhye" showed sucrose, fructose, glucose, maltose, limit dextrin and various size of maltooligosaccharides in HPLC and TLC analysis. Commercial Sikhye was found to contain 0.09% of limit dextrin and 0.2% of rice residue. Limit dextrin in commercial Sikhye showed both signal of $\alpha$-1,4- and $\alpha$-1,6-glucosidic linkage with its estimation ratio of 15:1 by 1H-NMR analysis. This limit dextrin was hydrolyzed to produce various size of maltooligosaccarides with more longer chain than that of traditional Sikhye by pullulanase. Limit dextrin was digested wit enzymes(30units/ml) of $\alpha$-amylase, $\alpha$-glucosidase and glucoamylase from Aspergillus awamori, sweet potato $\beta$-amylase and human salivary $\alpha$-amylase at 37$^{\circ}C$ for 1 hour, respectively. Hydrolysis rates of these amylases on it were higher than in case of traditional sikhye. $\alpha$-Glucosidase plus human salivary $\alpha$-amylase hydrolyzed it to 61.3%. Hydrolysis rates of these amylases on rice residue were lower than that of traditional Sikye. These results suggest that limit dextrin in commercial Sikhye is less effective than isomaltooligosaccharides in traditional Sikhye as a growth factor for Bifidobacterium while rice residue in commercial Sikhye is more effective than that in traditional Sikhye as dietary fiber.ary fiber.

• The Korean Journal of Food And Nutrition
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• v.10 no.3
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• pp.370-374
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• 1997

Commercial Sikhye was fermented by Saccharomyces cerevisiae for 10 day at 29$^{\circ}C$. Sucrose was hydrolyzed into glucose and fructose by invertase from the yeast, and the glucose and fructose were converted into ethanol by the yeast. Commercial Sikhye wine was found to contain 6.6% of ethanol, 0.32$\mu$mol/ml of amino acid, 226$\mu\textrm{g}$/ml of protein, and 2.5ml 0.1N NaOH of acidity, respectively, and its pH was 3.21. Limit dextrin in commercial rice Sikhye wine showed both signal of $\alpha$-1, 4- and $\alpha$-1, 6- glucosidic linkage with its estimation ratio of 25:1 by 1H-NMR analysis. The taste of rice Sikhye wine was similar that of wine.

• The Korean Journal of Food And Nutrition
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• v.12 no.2
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• pp.164-169
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• 1999

To develope the scientific preparation method of Dorean traditional rice drink 'Sikhye', effect of malt and commercial amylolytic enzymes in preparation of malt-Sikhye were studied. amylase activity of malt used in this study was 9,725unit/g. In malt-Sikhye preparation effective saccharifying conditions were 4% of malt 20% of rice at 6$0^{\circ}C$ for 5hour. Commercial amylolytic enzymes such as $\beta$-amylase(Bio-zyme ML Himaltosin GL) $\alpha$-amylase(Bokhabhyoso 5000, Teramyl and Fungamyl) and pulluanase(en-zyme CK-20) were not effective in saccharification for Sikhye preperation.

• Food Science and Preservation
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• v.14 no.6
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• pp.650-654
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• 2007

Ginseng sikhye is a unique beverage containing medicinal ingredients and having the unique flavor of ginseng. In this study, changes in the sugar composition of ginseng sikhye were investigated during the saccharification process. The concentration of ginseng sikhye was varied and the sugar content analyzed during the process. The amount of ginseng powder was varied from 3% to 12% in a mixture of malt (20 g), steamed rice (400 g) and 0.2 mL ${\alpha}$-amylase (Teramyl). With increasing time and temperature during the saccharification process, the sugar content in the ginseng sikhy eincreased, reaching levels similar to commercial sikhye. However, based on analysis of free sugars, the maltose content in ginseng sikhye was over 4.3%, which was higher than for commercial sikhye. Therefore, ginseng sikhye shows excellent marketability quality.

• The Korean Journal of Food And Nutrition
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• v.8 no.3
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• pp.165-171
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• 1995

Sikhye is a traditional sweet rice drink in Korea by $\beta$-amylase's saccharifing action. Sikhye has great potentiality for commercial beverage because of It's characteristic taste and flavors. But, the chemical compositions and production methods of Sikhye are little known. The total amount of carbohydrate of sixteen Sikhye selected in Korean market was 11~15%. The reducing sugar by the Somogyi-Nelson's method was measured 0.4~2% as maltose, which has little influence on the sweetness of Sikhye. While sucrose content was about 10% by the TLC and Seliwanoff analysis. It means that carbohydrate in Sikhye was almost sucrose. Furthermore the most of Sikhye has brown color and turbidity. To improve the quality of Korean Sikhye, it is necessary to increase the production of maltose and to reduce brown color and turbidity, without adding sucrose.

• Korean journal of food and cookery science
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• v.30 no.2
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• pp.129-138
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• 2014

This research aimed to develope squash sikhye containing retrograded rice flour using response surface methodology. For this, nonlinear regression equation was calculated with the setting of independent variables as retrograded rice flour containing resistant starch and squash, and dependent variables as viscosity, sugar content, pH, color, and sensory attributes. Under the experimental condition, the quality characteristics of squash sikhye were found as 6.20~6.25 for pH, $14.00{\sim}17.33^{\circ}Brix$ for sweetness, 2.64~4.45 cP for viscosity, 57.51~60.18 for lightness, 4.94~7.52 for redness, and 50.98~60.29 for yellowness. It also was revealed overall acceptability in sensory evaluation rated as 9.67~10.83 out of 15 point. These results showed statistically significant differences in quality attributes with the increase of retrograded rice flour and squash(p<0.05). Thus, optimal mixing quantity of squash and retrograded rice flour for squash sikhye was identified as 114 g and 65 g, respectively. Comparison of sensory qualities of four samples, namely squash sikhye with and without retrograded rice, and two commercial products, showed that squash sikhye including retrograded rice flour had the best quality in terms of color, taste, mouth feeling, flavor and overall acceptability (p<0.05). Thus the squash sikhye with retrograded rice flour can be the potential products as a health benefit beverage for the old adult and the young generation.

• Korean Journal of Food Science and Technology
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• v.40 no.3
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• pp.311-315
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• 2008

This study compared the quality characteristics of sikhye (a traditional Korean sweet rice drink) samples prepared with $N_2$-circulated low-temperature dry malt (RM) and commercial malts. The amylase activities of the malts and the physiochemical (brix, reducing sugar, turbidity, color) and sensory qualities of the sikhye samples were examined. The results showed that RM had higher ${\alpha}$-amylase and ${\beta}$-amylase activities than the commercial malts. And the sikhye made with RM had higher sugar and reducing sugar contents as compared to the samples made with commercial malts. There were no significant differences in L-values between the groups; however, the RM sikhye showed lower a- and b-values. Finally, the sensory evaluation results indicated that RM sikhye received higher sweetness, color, flavor, and overall acceptability scores than the samples made with commercial malts.