• Food Science and Biotechnology
• /
• v.18 no.1
• /
• pp.118-123
• /
• 2009

In order to find out the effect of low level of starch acetylation on physicochemical properties of potato starch, amylose content, digestibility of raw and gelatinized starch, thermal properties, pasting properties, and the swelling power of native and acetylated potato starches were measured. The amylose content was significantly lower in acetylated starch than in their counterpart native starches. Though a tendency in the decrease in digestibility of raw starch was observed with starch acetylation, acetylation did not alter the proportion of readily digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) of both raw and gelatinized potato starches. No clear increase in the swelling power was observed, however, the peak and onset gelatinization temperatures and the enthalpy required for starch gelatinization decreased with starch acetylation. Peak and breakdown viscosities were reduced due to acetylation of potato starch while final viscosity and set back were increased.

• Preventive Nutrition and Food Science
• /
• v.16 no.4
• /
• pp.339-347
• /
• 2011

Flour and isolated starch from chickpea (desi type, 328S-8) were evaluated for their in vitro digestibility and physicochemical properties. The protein content, total starch content and apparent amylose content of chickpea flour and isolated starch were 22.2% and 0.6%, 45.8% and 91.5%, and 11.7% and 35.4%, respectively. Chickpea starch granules had an oval to round shape with a smooth surface. The X-ray diffraction pattern of chickpea starch was of the C-type and relative crystallinity was 24.6%. Chickpea starch had only a single endothermic transition (13.3 J/g) in the DSC thermogram, whereas chickpea flour showed two separate endothermic transitions corresponding to starch gelatinization (5.1 J/g) and disruption of the amylose-lipid complex (0.7 J/g). The chickpea flour had a significantly lower pasting viscosity without breakdown due to low starch content and interference of other components. The chickpea starch exhibited significant high setback in the viscogram. The average branch chain length, proportion of short branch chain (DP 6~12), and long branch chains (DP${\geq}$37) of isolated chickpea starch were 20.1, 20.9% and 9.2%, respectively. The rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) contents of chickpea flour and starch were 9.9% and 21.5%, 28.7% and 57.7%, and 7.1% and 9.3%, respectively. The expected glycemic index (eGI) of chickpea flour (39.5), based on the hydrolysis index, was substantially lower than that of isolated chickpea starch (69.2).

• Korean journal of food and cookery science
• /
• v.32 no.4
• /
• pp.524-530
• /
• 2016

Purpose: The properties of starch and starch gel prepared from a newly inbred sweet potato, Daeyumi were compared to the properties of starch and starch gel prepared from Sinyulmi which is a well known mealy type sweet potato. Methods: The starch was isolated by using the alkaline steeping method. Physicochemical, pasting, and thermal properties, and crystallinity were measured. The texture properties of starch gel (10%, w/w) were examined. Results: The amylose contents of Daeyumi and Sinyulmi starches were 25.57% and 22.59%, respectively. The initial pasting temperature of Daeyumi starch was significantly higher than that of Sinyulmi starch (p<0.05), but other paste viscosities were not different. The peak and conclusion temperatures of Daeyumi starch were higher than those of Sinyulmi starch by differential scanning calorimetry. The shape of Daeyumi starch gel was more clear and rigid than the shape of Sinyulmi starch gel. The surface and the upper side of Daeyumi starch gel were smoother than the surface and the upper side of Sinyulmi starch gel. Hardness and gumminess were higher in Daeyumi starch gel than in Sinyulmi starch gel. The crystallinity types of Daeyumi and Sinyulmi starches were $C_b$ and A types, respectively, but starch gels showed an amorphous type. Conclusion: Therefore, it is suggested that Daeyumi starch would have better physicochemical properties and higher quality of starch gel than Sinyulmi starch.

• Journal of the East Asian Society of Dietary Life
• /
• v.26 no.5
• /
• pp.407-417
• /
• 2016

Effects of resistant starch as a functional substitute on the quality of Yukwa were determined. Replacement ratios of resistant starch were 2, 4, and 6% of glutinous rice flour. Regarding pasting properties of Yukwa dough replaced with resistant starch, initial pasting temperature significantly increased and peak viscosity significantly decreased with increasing resistant starch. The moisture contents of bandegi and Yukwa base replaced with resistant starch were higher than that of the control. The expansion ratio of Yukwa base replaced with resistant starch significantly decreased with increasing resistant starch, and there were no significant differences in the oil absorption ratio. Lightness (L) of Yukwa base replaced with resistant starch increased significantly with increasing resistant starch. Appearance of Yukwa base replaced with resistant starch showed a shortened length and increased width with increasing resistant starch, and cross-section showed an oval shape, fine air cell distribution, and increased outer layer thickness. Hardness and peak number increased significantly with increasing resistant starch. The overall acceptability of Yukwa base replaced with 6% resistant starch was the highest among the samples, but the result was not significant. The above results show that resistant starch substitution in Yukwa improved the texture and further could improve health functionality due to its dietary fiber content. Resistant starch was appropriate as a 6% replacement for glutinous rice flour in Yukwa.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.2
• /
• pp.244-250
• /
• 1994

Starch phosphates were prepared by dry heating method using sodium triphosphate as a substitution reagent and their physicochemical properties were investigated with the chucheongbyeo and samkangbyeo. The solubility and swelling power of rice starches were increased by phosphorylation reaction. The solubility of the chucheongbyeo was greater than that of samkangbyeo , but the swelling power was appeared in vice versa. The transparency of raw starch was increased at the 6$0^{\circ}C$, but phosphorylated rice starch was begun to increase from 5$0^{\circ}C$. Light transmittance was higher inthe phosphorylate drice starch. The lightness of phosphyorylated rice starch decreased more than that of raw starch. Whereas the yellowness of phosphorylated rice starch increased. The temperature of initial gelatinization of the phosphorylated chucheong and samkang rice starch was shown to 5$0^{\circ}C$ and 53$^{\circ}C$, respectively. lowering 14-15$^{\circ}C$ in temperatureby the phosphorylation . The viscosity as well as by the phosphorylation reaction was raised 7.4-8.4 times, respectively. The hardness, adhesiveness, cohesiveness and texture which is rheological properties of starch gel increased by the phosphoryulation reaction. The chucheong rice starch gel was slightly higher in its rheolgocial values thanthat of the samkang rice starch gel. The rice starch particles were shown to polygonal structure, but they were deformed in the phosphorylated starch.

• Journal of the Korean Home Economics Association
• /
• v.26 no.3
• /
• pp.93-102
• /
• 1988

Rheological properties of cowpea and mung bean starch gels and pastes were investigated and compared with Instron Universal Testing machine and Brabender Viscometer. As the result of puncture test of gels, yield point force of mung bean starch gel was higher than that of cowpea starch gel. Compression coefficient of cowpea starch gel calculated by Bourne's equation was lower than that of mung bean starch gel. the stress relaxation test showed that viscoelastic properties of cowpea and mung bean starch gels may be represented by six element Maxwell model consisting of three Maxwell element in parallel. Cowpea and mung bean starch pastes showed bingham pseudoplastic behavior in 3, 5, 6, 7 and 8%. The consistency index in 7∼8% of cowpea starch paste were lower than those of mung bean starch paste. concentration dependence on consistency index and yield stress in mung bean starch were higher than those of cowpea starch. The yield stress of starch pastes was significantly correlated with yield point force by puncture test (r=0.996).

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.16 no.2_3
• /
• pp.59-65
• /
• 2010

Starch was modified with epichlorohydrin(ECH) to improve the miscibility with LDPE and LLDPE. Native starch or epichlorohydrin treated starch was mixed with grycerol and LDPE/LLDPE resin using a kneader and extruded using a single screw extruder to make pallets. The pallets were compression-molded at 145 into composite boards to evaluate their color, oxygen permeation, mechanical and thermal properties, and degradability under UV irradiation. Sheets with epichlorohydrin treated starch generally showed higher L-value than that of native starch blend sheets. The hunter b-values in both native starch blends and epichlorohydrin treated starch blends increased with Increasing starch contents. Tensile strength and percent elongation of sheets decreased with increasing starch contents. Tensile strength and percent elongation of sheets decreased with increasing starch contents. The degradability of blends under UV radiation increased with increasing starch contents in both blend types. The results represents that crosslinking of starch with epichlorohydrin may be a good method to improve miscibility of starch with petroleum-based materials.

• The Korean Journal of Food And Nutrition
• /
• v.9 no.4
• /
• pp.424-429
• /
• 1996

In an attempt to evaluate the effect of six starch sources-potato starch acetate, corn starch acetate, waxy corn starch, corn starch, potato starch, and wheat starch on properties of frozen noodle, amylograph characteristics of starch-wheat flour composites, cooking quality, maximum cutting force and sensory properties of cooked frozen noodles were examined. Compared with 100% wheat flour as control, potato starch acetate and potato starch-wheat flour composites had slightly lower initial pasting temperature and wheat flour composites with acetylated starches, waxy corn starch and potato starch had slightly higher maximum peak viscosity. At cooking quality examination of noodles made from wheat flour-starch composites, volume and weight of cooked noodles were increased and cook loss was decreased with the addition of acetylated starches and waxy corn starch. Maximum cutting forces of cooked frozen noodles containing more than 15% of potato starch acetate and only 15% of corn starch acetate were higher than that of control. Other starches except potato starch improved sensory properties of cooked frozen noodles and the greatest positive effect was acetated potato starch.

• KSBB Journal
• /
• v.13 no.5
• /
• pp.621-625
• /
• 1998

The raw starch hydrolysis by amylase prepared from alkaline-tolerant Bacillus sp. were investigated. Degree of hydrolysis(%) of 5%(w/v) raw rice, corn and potato starch by this enzyme were about 40, 25 and 20%, respectively. The hydrolysis action on raw starch by change of blue value was similar to the action pattern of exo ${\beta}$-amylase. The hydrolysis products of rice starch were mainly glucose and maltose. Oligosaccarides were also detected. From the above results, this enzyme was considered as exo type ${\alpha}$-amylase. This enzyme activity on the raw starch and the gelatinized starch were 28.40 and 86.60 IU/mg protein, respectively, and the ratio of raw starch-digesting activity to gelatinized starch-digesting activity (raw starch digestivity) was about 32%. The Km values for the raw and the gelatinized starch were 4.22 and 3.0mg/mL, respectively, and the VmaX values were 0.20 and 0.31mg/mL/min, respectively.

• Journal of Environmental Science International
• /
• v.13 no.9
• /
• pp.827-833
• /
• 2004

The biodegradability of vinyl acetate acrylate resin and com starch blend was studied by determination of the reduced sugars produced after enzymatic hydrolysis. The starch hydrolysis reaction by $\alpha-amylase$ was achieved within 5 minutes. Optimal ranges of temperature and pH for the starch hydrolysis by $\alpha-amylase$ were around $80^{\circ}C$ and 6.5-7.2, respectively. The biodegradability of the starch-filled acrylate films increased as the content of starch increased. The biodegradation of starch in the starch-filled acrylate film by $\alpha-amylase$ was about 48.6% of that of pure starch. This value of biodegradable starch-filled acrylate film gave a good result with enzymatic shortcut test. The surface morphologies of the starch-filled acrylate film after enzymatic hydrolysis were investigated by scanning electron microscopy (SEM).