• Title, Summary, Keyword: steeping temperature

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Effect of Soaking Time and Steeping Temperature on Biochemical Properties and γ-Aminobutyric Acid (GABA) Content of Germinated Wheat and Barley

  • Singkhornart, Sasathorn;Ryu, Gi-Hyung
    • Preventive Nutrition and Food Science
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    • v.16 no.1
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    • pp.67-73
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    • 2011
  • The objective of this research was to investigate the effects of soaking time (6, 12 and 24 hr) and steeping temperature (25, 30 and $35^{\circ}C$) on germination time, germination percentage and weight loss of wheat and barley. Changes in chemical composition (such as protein, fat, and ash), reducing sugar content, enzyme activity and pasting profile and GABA ($\gamma$-animobutyric acid) content of germinated wheat and barley were also evaluated. The results clearly suggest that the short soaking time and lower steeping temperature significantly decreased germination time and weight loss, while germination percentage increased. Regarding the chemical composition, the protein content of wheat and barley was slightly increased after germination but there was no significant difference in content of crude fat and ash of both germinated cereals. The reducing sugar content of both germinated cereals decreased as the steeping temperature increased from $25^{\circ}C$ to $35^{\circ}C$. Increasing soaking time and steeping temperature led to increased amylase activity, and also corresponded to reduced paste viscosity. The highest GABA content that occurred with soaking times of 6 and 12 hr and a steeping temperature of $35^{\circ}C$ was 1,467.74 and 1,474.70 ${\mu}g/g$ for germinated wheat and 2,108.13 and 1,691.85 ${\mu}g/g$ for germinated barley. This study indicated that the optimum germination process for wheat and barley is a low steeping temperature and a short soaking time.

Physicochemical and Gelatinization Properties of Glutinous Rice Flour and Starch Steeped at Different Conditions (수침한 찹쌀가루와 전분의 이화학적 및 호화 특성)

  • 최은정;김향숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.1
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    • pp.17-24
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    • 1997
  • The effects of steeping on the physicochemical and gelatinization characteristics of glutinous rice flour and its starch were studied. Steeping conditions were 1 day at 25"C,7 days at 2iC and 7 days at 35"C. Crude protein, lipid and ash content were decreased br steeping. It was observed with scanning electron microscopy that endosperm cell wall of glutinous rice flour was diminished by steeping. Although morphology of the glutinous rice starch granules was not affected, the size was decreased by steeping. Density and water binding capacity(WBC) of glutinous rice flour and its starch were changed by steeping. X-ray diffraction pattern of glutinous rice starch was A type and was not affected by steeping. Swelling power of glutinous rice flour and its starch was increased but solubility was decreased by steeping. In Brabender amylographic examination, peak viscosity of untreated glutinous rice flour was very low and increased enormously by steeping resulting in the similar Brabender viscosity pattern to its starch. The gelatinization temperature examined by X-ray diffractometry was lowered by steeping. And the degree of gelatinization under the conclusion temperature increased with increasing of steeping Period and temperature.mperature.

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Gelatinization Properties of Starch during Steeping Condition of Potato (감자의 수침조건에 따른 전분의 호화 특성)

  • 정난희;김경애;전은례
    • Korean journal of food and cookery science
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    • v.16 no.5
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    • pp.431-436
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    • 2000
  • Gelatinization properties of potato starches which were prepared by steeping at 10 ${\pm}$ 1$^{\circ}C$ or 25 ${\pm}$ 1$^{\circ}C$ for 11 days were investigated. The pasting and initial gelatinization temperatures measured by rapid visco-analyzer (RVA) were increased, but the peak and trough viscosities of potato starch were decreased by steeping. The onset temperature, peak temperature, conclusion temperature, and enthalpy of gelatinization were increased by steeping as measured by DSC. The contents of hot-water-soluble carbohydrate and amylose in potato starch were decreased by steeping.

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Gelatinization Properties of Starch during Steeping of Potato (감자의 수침에 따른 전분의 열 호화 특성)

  • 정난희;김경애;김성곤;서복영;전은례
    • Korean journal of food and cookery science
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    • v.14 no.3
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    • pp.213-218
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    • 1998
  • The changes in gelatinization patterns of potato were investigated while steeping in water for 7 days at 30${\pm}$1$^{\circ}C$. The transmittance of 0.1% starch suspension was increased rapidly from 60$^{\circ}C$ in raw starch and the starch steeped for 2 days, and increased rapidly from 65$^{\circ}C$ in the starch steeped for 4 and 6 days. As the steeping period increased, the transmittance was decreased at above condition. The gelatinization temperature of the starch measured by differential scanning calorimetry was increased from 62.79$^{\circ}C$ to 63.72$^{\circ}C$ as the steeping period increased. The gelatinization enthalpy reached the maximum in the starch steeped for 4 days. By amylograph, the initial gelatinization temperature was increased from 66$^{\circ}C$ to 84$^{\circ}C$ as the steeping period increased. Peak viscosity was decreased during steeping and the starch steeped for 5 days had no peak viscosity. Peak height after cooling to 50$^{\circ}C$ was increased up to the 4th day and began to decrease. As the steeping period increased, there was much loss of birefringence at higher temperature. The crystallinity by X-ray diffraction disappeared from 65$^{\circ}C$.

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Physicochemical Properties of Rice Affected by Steeping Conditions (수침이 멥쌀의 이화학적 성질에 미치는 영향)

  • Kim, Sung-Kon;Bang, Jung-Bum
    • Korean Journal of Food Science and Technology
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    • v.28 no.6
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    • pp.1026-1032
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    • 1996
  • The effects of steeping temperature $(7^{\circ},\;15^{\circ},\;20^{\circ}\;and\;30^{\circ}C)$ and steeping time $(2{\sim}14\;hr)$ on the physicochemical properties of milled rice (variety; Chucheongbyeo) were investigated. The pH of the steep water decreased as the steeping time increased, which was more pronounced at higher steeping temperature. The solid loss was about 4.0% during steeping. The contents of protein, fat and ash decreased during steeping, which was greater at elevated temperature. The lightness of rice was slightly increased, and the yellowness was decreased upon steeping. The water-binding capacity of rice was increased during steeping at above $15^{\circ}C$. The slight increase of the swelling power of rice at $80^{\circ}C$ was observed upon steeping. The maximum wavelengh for the rice flour-iodine complex was moved to a higher wavelengh, but X-ray diffraction patterns remained constant regardless the steeping conditions. The pasting properties of rice flour (10%) by amylograph indicated that the peak viscosity increased as the steeping time was increased at all steeping temperatures. The steeping resulted in the greater breakdown and the 1ower setback. The log peak viscosity showed a linear relationship with the steeping time. The activation energy and $Q_{10}$ value for the visciosity increase rate was 2, 320 cal/mole and 1.14, respectively.

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Optimization of Rice (Oryza Sativa) Malting Process by Second-Order Experimental Design

  • Nguyen, Thach Minh;Nguyen, Xich Lien;Hoang, Kim Anh;Lee, Soo
    • Journal of the Korean Applied Science and Technology
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    • v.25 no.3
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    • pp.282-290
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    • 2008
  • The malting process of rice (OM4080 variety from Mekong Delta Rice Research Institute) was studied under pilot condition plan by means of the second-order experimental design. Processing parameters, such as the steeping time (0-60 hrs), steeping temperature ($5-45^{\circ}C$), germination time (0-8 days), germination temperature ($5-45^{\circ}C$) and gibberellin concentration (0-2 mg/kg) were investigated. As a result, all germination conditions, especially germination time, germination temperature, and gibberellin concentration had a significant effect on the malting loss, amylase activity and starch content. The protein content was not clearly affected by any conditions. The optimum conditions for malting process (with highest amylase activity) were as follows: 30 hrs of steeping time, $30-35^{\circ}C$ of steeping temperature, 5-5.5 days of germination time, $25^{\circ}C$ of germination temperature, and 1.5 mg/kg of giberrellin concentration.

Gelatinization and Retrogradation Properties of Modified Starch by Steeping Sweet Potato (고구마 수침에 의한 변성 전분의 호화와 노화 특성)

  • Lee, Shin-Kyung;Shin, Mal-Shick
    • Korean Journal of Food Science and Technology
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    • v.26 no.5
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    • pp.638-643
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    • 1994
  • Gelatinization and retrogradation properties of modified starches which were prepared by steeping sweet potato at $40^{\circ}C$ for 2, 4, 7 and 10 days were investigated. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C\;and\;1.32\;cal/g$, respectively, but those of modified starch were increased by steeping. In gelatinization by alkali, starches with 2, 4 and 7 day steeping showed higher viscosities than untreated starch, whereas the viscosities of starches with 10 day steeping decreased. The clarities in paste decreased during storage in all starches and decreased in starches with steeping. The degrees of retrogradation by ${\alpha}-amylase-iodine$ method were higher in starches with steeping than untreated starch. The enthalpy of retrograded starches by DSC increased by steeping except 4 day steeping starch. The sweet potato extract containing sugar inhibited the retrogradation of starch paste and the degree were higher in residual starches than in untreated starch.

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Effect of Elevated Steeping Temperature on Properties of Wet-milled Rice Flour (가온 수침처리가 습식제분 쌀가루의 특성에 미치는 영향)

  • Kim, Sang-Sook;Kang, Kyung-A;Choi, So-Yeon;Lee, Young-Tack
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.3
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    • pp.414-419
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    • 2005
  • Newly harvested milled rice and stored milled rice for 2 years were steeped at the elevated temperatures of 40, 50, and 60℃ for 2hr, and physicochemical properties of the wet-milled rice flour were investigated. The lightness of rice flour was slightly higher in the newly harvested milled-rice, while yellowness was higher in the stored milled rice. For both newly harvested and stored milled rice, WAI, WSI, and gel consistency increased as steeping temperature increased. The amylograph pasting properties indicated that increasing steeping temperature increased peak viscosity. The differential scanning calorimetry (DSC) results of the rice flour showed that increasing steeping temperature increased onset and peak temperatures, with reduced gelatinization enthalphy, suggesting partial annealing occured. Particle size of rice flour from newly harvested milled rice was larger than that from stored milled rice.

Changes in Microflora, Enzyme Activities and Microscopic Structure of Waxy Rice and Steeping Water in Response to Different Steeping Conditions During Preparation of Gangjung (강정 제조시 찹쌀의 수침조건에 따른 찹쌀과 수침액의 미생물상, 효소활성 및 미세구조 변화)

  • Kim, Haeng-Ran;Kim, Kyung-Mi;Kim, Kwang-Ok
    • Korean Journal of Food Science and Technology
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    • v.41 no.6
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    • pp.644-651
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    • 2009
  • This study was conducted to investigate the effects of steeping periods and temperatures of waxy rice on the microflora and enzyme activities of steeping water and waxy rice, as well as on the microscopic structures of waxy rice during the preparation of gangjung. When the steeping water was 15 and $35^{\circ}C$, yeast and lactic acid bacteria were the major microflora after 1 day. After 11 days, Lactobacillus spp. were the major bacteria, while Bacillus spp. were the primary microflora after 21 days. At $25^{\circ}C$ the primary species were Bacillus spp., Leuconostoc spp., and Bacillus spp. after 1, 11 and 21 days, respectively. The $\alpha$-amylase activity of steeping water increased proportionally with the increase of temperature and period, while the protease activity tended to increase for 11 days, but decreased at 21 days. The enzyme activities of the steeped waxy rice, especially the $\alpha$-amylase activity, decreased with higher steeping temperature, while the $\beta$-amylase and glucoamylase activity remained constant for up to 21 days. Observation using scanning electron microscopy indicated that intracellular cleavage of steeped waxy rice endosperm resulted in a rough surface morphology due to the exposure of polygonal starch granules. Tiny pinholes on the surface of waxy rice starch granules were also observed after steeping for 11 days.

Optimizing Steeping Conditions of Waxy Rice Based on the Sensory Properties of Gangjung (a Traditional Korean Oil-Puffed Snack) (강정의 관능적 특성에 의한 찹쌀의 수침조건 최적화)

  • Kim, Haeng-Ran;Kim, Kyung-Mi;Kim, Kwang-Ok
    • Korean Journal of Food Science and Technology
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    • v.41 no.4
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    • pp.464-470
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    • 2009
  • This study was conducted to determine the optimal steeping period and temperature for Gangjung production, using response surface methodology based on the previously reported sensory characteristics. Five sensory attributes ('degree of expansion', 'sourness', 'butyric acid flavor', 'hardness' and 'degree of melting'), which showed high variability explained ($R^2$) and recognized to be important for the quality of Gangjung were selected for optimization. As a result, the optimal steeping temperature and period of waxy rice were determined to be $31.5^{\circ}C$ and 9 days, respectively.