The effect of water on heating wheat starch-water mixtures of water content (between 2.8% and 90%) has been observed by differential scanning calorimetry. Four endothermic transitions were observed for wheat starches heated in the presence of limited water (moisture levels of 40,50%). These transitions appears to be due to melting of amylopectin crystallites, amylose-lipid, and arnylose. The heat decomposition temperature range of wheat starch were 253-302OC and the plasticization effect according to the amount of water was small. The melting temperature obtained by extrapolation to zero volunme fraction of water were 234°C for M1 DSC endotherm, 254.3OC for M2 DSC endotherm, 267.8"C for M3 DSC endotherm. EinfluB des Feuchtigkeitsgehaltes auf das Schmelren vonWeirenstllrke. Der EinfluB von Wasser auf die Erwarmung von Starke-Wassermischungen (zwischen 2,s und 90%) wurde durch Differential-Raster-Calorimetrie beobachtet. Vier endotherme Ubergange wurden bei Weizenstarken beobachtet, die in Gegenwart begrenzter Wassermengen erhitzt worden waren (Feuchtigkeitsgehalte 40,50%). Diese Ubergange scheinen verantwortlich zu sein fur das Schmelzen von Amylopektinkristalliten, Amylose-Lipid und Amylose. Der Warmeabbau-Temperaturbereich von Weizenstarke war 253-302OC, und die Plastifizierungswirkung war entsprechend der Wassermenge gering. Die Schmelztemperatur, die durch Extrapolation auf die Nullvolumen-Wasseranteile erhalten wurde, betrug fur die M1-DSC-endotherme 234"C, fur die M2-DSC-Endotherme 254OC und fur die M3-DSC-Endotherme 267OC.

Cereal Chem. 78(2): [186][187][188][189][190][191][192] Differential scanning calorimetry (DSC) was used to study the effect of sucrose on wheat starch glass transition, gelatinization, and retrogradation. As the ratio of sucrose to starch increased from 0.25:1 to 1:1, the glass transition temperature (T g , T g ′) and ice melting enthalpy (∆H ice ) of wheat starch-sucrose mixtures (with total moistures of 40-60%) were decreased to a range of -7 to -20°C and increased to a range of 29.4 to 413.4 J/g of starch, respectively, in comparison with wheat starch with no sucrose. The T g ′ of the wheat starch-sucrose mixtures was sensitive to the amount of added sucrose, and detection was possible only under conditions of excess total moisture of >40%. The peak temperature (T m ) and enthalpy value (∆H G ) for gelatinization of starch-sucrose systems within the total moisture range of 40-60% were increased with increasing sucrose and were greater at lower total moisture levels. The T g ′ of the starchsucrose system increased during storage. In particular, the significant shift in T g ′ ranged between 15 and 18°C for a 1:1 starch-sucrose system (total moisture 50%) after one week of storage at various temperatures (4, 32, and 40°C). At 40% total moisture, samples with sucrose stored at 4, 32, and 40°C for four weeks had higher retrogradation enthalpy (∆H) values than a sample with no sucrose. At 50 and 60% total moisture, there were small increases in ∆H values at storage temperature of 4°C, whereas recrystallization of samples with sucrose stored at 32 and 40°C decreased. The peak temperature (T p ), peak width (δT), and enthalpy (∆H) for the retrogradation endotherm of wheat starch-sucrose systems (1:0.25, 1:0.5, and 1:1) at the same total moisture and storage temperature showed notable differences with the ratio of added sucrose. In addition, T p increased at the higher storage temperature, while δT increased at the lower storage temperature. This suggests that the recrystallization of the wheat starch-sucrose system at various storage temperatures can be interpreted in terms of δT and T p .The phase transitions associated with ordering and disordering, such as glass transition, gelatinization, and retrogradation in starch systems have been intensively investigated with differential scanning calorimetry (DSC) (Donovan 1979; Zeleznak and Hoseney 1987a,b;Slade and Levine 1988;Kalichevsky et al 1992).The glass transition temperature (T g , T g ′) in starch decreases with increasing water content due to the plasticization effect of water (Slade and Levine 1987). The T g of starch systems with water contents >20% drops below room temperature (Zeleznak and Hoseney 1987a) and below 0°C for water contents ≥50% (Slade and Levine 1988). At temperatures below T g , the material becomes a glassy solid and molecular motion is so slow that crystallization does not occur in a realistic period of time. At temperatures above T g , however, the material is a rubbery liquid and sufficient motion of the polymer can occur, allowing a retro...

Leuconostoc lactis SBC001, isolated from chive, produces glucansucrase and synthesizes oligosaccharides through its enzymatic activity. This study was conducted to optimize oligosaccharide production using response surface methodology, analyze the structure of purified oligosaccharides, and investigate the prebiotic effect on 24 bacterial and yeast strains and the anti-inflammatory activity using RAW 264.7 macrophage cells. The optimal conditions for oligosaccharide production were a culture temperature of 30 °C and sucrose and maltose concentrations of 9.6% and 7.4%, respectively. Based on 1H-NMR spectroscopic study, the oligosaccharides were identified as gluco-oligosaccharides that consisted of 23.63% α-1,4 glycosidic linkages and 76.37% α-1,6 glycosidic linkages with an average molecular weight of 1137 Da. The oligosaccharides promoted the growth of bacterial and yeast strains, including Lactobacillus plantarum, L. paracasei, L. johnsonii, Leuconostoc mesenteroides, L. rhamnosus, and Saccharomyces cerevisiae. When lipopolysaccharide-stimulated RAW 264.7 cells were treated with the oligosaccharides, the production of nitric oxide was decreased; the expression of inducible nitric oxide synthase, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-10 was suppressed; and the nuclear factor-kappa B signaling pathway was inhibited. In conclusion, the gluco-oligosaccharides obtained from Leu. lactis SBC001 exhibited a prebiotic effect on six bacterial and yeast strains and anti-inflammatory activity in RAW 264.7 macrophage cells.

Differential Scanning Calorimetry (DSC) was used to study retrogradation of wheat starch. For storage at 4°C, enthalpy (ΔH) values of retrogradation endotherm (recrystallization) of wheat starch containing various moisture levels (25–80%) slowly continued to increase except in samples with moisture level of 50, 60 and 70%. For storage at 26°C and 32°C, most recrystallization of wheat starch occured within one and two weeks of storage time, while recrystallization with a moisture level of 50% at 26°C occurred for 4 weeks. The peak temperatures of retrogradation endotherm at various moisture levels (25–80%) after 4 weeks of storage time increased largely as the storage temperatures increased from 4 to 32°C. The enthalpy values of retrogradation endotherm after 4 weeks of storage occurred to a greater extent at a lower storage temperature. The glass transition temperature and starch recrystallization have a close relationship. In the recrystallization of wheat starch, the nucleation and propagation rate after 4 weeks of storage can be converted into enthalpy and peak temperature of retrogradation endotherm.

Leuconostoc lactis CCK940, which exhibits glycosyltransferase activity, produces oligosaccharides using sucrose and maltose as donor and receptor molecules, respectively. The oligosaccharides produced were purified by Bio-gel P2 chromatography and the purified oligosaccharides (CCK-oligosaccharides) consisted of only glucose. 1H-NMR analysis revealed that the CCK-oligosaccharides were composed of 77.6% α-1,6 and 22.4% α-1,4 glycosidic linkages, and the molecular weight of the CCK-oligosaccharides was found to be 9.42 × 102 Da. To determine the prebiotic effect of the CCK-oligosaccharides, various carbon sources were added in modified media. Growth of six probiotic strains, Lactobacillus casei, L. pentosus, L. plantarum, Weissella cibaria, Bifidobacterim animalis, and Saccharomyces cerevisiae, was better when the CCK-oligosaccharides were used as the sole carbon source compared to fructo-oligosaccharides, which are widely used as prebiotics. These results showed that the CCK-oligosaccharides produced from Leu. lactis CCK940 could serve as good candidates for novel prebiotics.