Improvement of functional and rheological features of tigernut tuber starch by using gum derived from Chinese quince seeds

Bactericidal effect of ultrasound on glutinous rice during soaking and its influence on physicochemical properties of starch and quality characteristics of sweet dumplings

The soaking process of glutinous rice allows the growth and reproduction of microorganisms, which can easily cause food safety problems. In this work, the effects of different ultrasonic powers (150 W, 300 W, 450 W, and 600 W) on the bactericidal effect of glutinous rice, the physicochemical properties of starch and the quality characteristics of sweet dumplings were studied. Compared with soaking for 0 and 2 h, sonication of glutinous rice after soaking for 4 h was more effective at reducing the number of microorganisms in soaked glutinous rice, and the bactericidal effect increased with increasing ultrasound intensity. After 30 min, the total number of bacteria decreased by 2.04 log CFU/g. Moreover, ultrasonic treatment destroys the grain structure of glutinous rice starch, resulting in the formation of dents and cracks on the starch surface, increasing the amylose content, improving its expansion, reducing its short-range order and relative crystallinity, and altering its gelatinization characteristics. In addition, ultrasonic treatment increased the soup transparency of sweet dumplings from 51.8 % to 63.95 %, reducing their hardness, chewiness and adhesiveness. In summary, ultrasonic treatment can not only effectively kill microorganisms in soaked glutinous rice but also improve the quality of glutinous rice dumplings by changing the physicochemical properties of glutinous rice starch. The results of this study provide theoretical support for the application of ultrasonic technology in glutinous rice food production.

Effect of Cyperus esculentus polysaccharide on Cyperus esculentus starch: Pasting, rheology and in vitro digestibility

This study investigated the effects of varying amounts of added Cyperus esculentus polysaccharide (CEP) on the physicochemical and structural properties, as well as in vitro digestibility, of homologous Cyperus esculentus starch (CES). Compared to CES, the CES-CEP complexes showed reduced peak viscosity and breakdown value, and improved thermal paste stability of starch. Rheological properties showed that adding CEP reduced the consistency coefficient and pseudoelasticity of the complexes, thus increasing their resistance to shear thinning. FTIR analysis suggested the absence of covalent binding between CES and CEP. SEM showed a more homogeneous and dense gel structure, particularly in the CES-1.0%CEP sample. During in vitro digestion, the content of resistant starch in the complexes increased after CEP was added. Analysis of the interaction forces showed that the CES-CEP complexes had stronger hydrogen bonding and electrostatic interaction. This study offers valuable insights into the potential applications of CEP in starch-based foods.

The Effects of Tremella fuciformis Polysaccharide on the Physicochemical, Multiscale Structure and Digestive Properties of Cyperus esculentus Starch

In this study, we have investigated the effects of Tremella fuciformis polysaccharide (TP) on the pasting, rheological, structural and in vitro digestive properties of Cyperus esculentus starch (CS). The results showed that the addition of TP significantly changed the pasting characteristics of CS, increased the pasting temperature and pasting viscosity, inhibited pasting, reduced the exudation of straight-chain starch and was positively correlated with the amount of TP added. The addition of the appropriate amount of TP could increase its apparent viscosity and enhance its viscoelasticity. The composite system of CS/TP exhibited higher short-range ordered structure and solid dense structure, which protected the crystal structure of CS, but was related to the amount of TP added. In addition, the introduction of TP not only decreased the in vitro digestion rate of CS and increased the content of slow-digestible starch (SDS) and resistant starch (RS), but also reduced the degree of digestion. Correlation studies established that TP could improve the viscoelasticity, relative crystallinity and short-range order of the CS/TP composite gel, maintain the integrity of the starch granule and crystalline structure, reduce the degree of starch pasting and strengthen the gel network structure of CS, which could help to lower the digestibility of CS.

Evaluation of Quality Properties of Brown Tigernut (Cyperus esculentus L.) Tubers from Six Major Growing Regions of China: A New Source of Vegetable Oil and Starch

Tigernut has been recognized as a promising resource for edible oil and starch. However, the research on the quality characteristics of tigernut from different regions is lagging behind, which limits the application of tigernut in food industry. Tigernut tubers were obtained from six major growing regions in China, and the physicochemical properties of their main components, oil and starch, were characterized. Tigernut tubers from Baoshan contained the most oil (30.12%), which contained the most β-carotene (130.4 µg/100 g oil) due to high average annual temperature. Gas chromatography analysis and fingerprint analysis results indicated that tigernut oil (TNO) consists of seven fatty acids, of which oleic acid is the major component. Changchun TNO contained the least total tocopherols (6.04 mg/100 g oil) due to low average annual temperature. Tigernut tubers from Chifeng (CF) contained the most starch (34.85%) due to the large diurnal temperature range. Xingtai starch contained the most amylose (28.4%). Shijiazhuang starch showed the highest crystallinity (19.5%). Anyang starch had the highest pasting temperature (76.0°C). CF starch demonstrated superior freeze-thaw stability (syneresis: 50%) due to low mean annual precipitation. The results could be further applied to support tigernut industries and relevant researchers that looks for geographical origin discrimination and improvements on tigernut quality, with unique physicochemical and technological properties.

The impact of different concentrations of hyaluronic acid on the pasting and microstructural properties of corn starch

Starch aging in starchy foods is a major problem affecting their quality. In order to improve the viscosity and textural properties of native starch gelatinization and retrogradation, this study investigated the effect of hyaluronic acid (HA) at different concentrations (2 %, 4 %, 6 % w/w) on the pasting and microstructure of corn starch (CS). The findings revealed that the addition of HA significantly enhanced the peak viscosity, solubility, and water-holding capacity of the CS-HA mixtures. Moreover, it reduced the pasting temperature, swelling force, and leaching of amylose. All the mixtures exhibited shear thinning and thixotropic properties. The CS-HA mixtures created a thicker pseudoplastic system with significantly enhanced shear stability. The structures of the mixtures were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. It was observed that HA effectively inhibited short-term retrogradation of starch, enhanced the interaction between CS and HA, and formed a dense honeycomb three-dimensional mesh structure. In conclusion, as a novel anionic hydrocolloid, HA holds great potential to improve the retrogradation properties of starch-based products.

Insights into the interaction of CaCl2 and potato starch: Rheological, structural and gel properties

High viscosity of starch greatly limit its application in some specific foods, in this work, a novel low-viscosity potato starch (PS) was developed via crosslinking between PS (3 %, w/v) and Ca²⁺ to investigate the effect of CaCl₂ concentration (0.1-5 % CaCl₂, w/v) on the rheological behaviors, structural and gel properties of PS. The results showed that peak viscosity (PV), trough viscosity (TV), final viscosity (FV), and breakdown viscosity (BD) of pasting curves of CaCl₂-treated PS were significantly reduced compared with the native PS. The CaCl₂ treatment also decreased the firmness of the PS gel and increased its pasting temperature (PT) and gelatinization enthalpy (∆H). Moreover, The CaCl₂ treatment also led to more organized crystallites in the PS granules as affected by the slight increase in the ratio of 1044/1015 cm^-1 in the FT-IR analysis, reduced the homogeneity of ordered structures inside granules as indicated by the increase in conclusion temperature (T_c)-onset temperature (T_o) in DSC analysis, and decreased relatively crystallinity revealed by XRD analysis. The findings of this study indicated CaCl₂-treated PS could serve as food ingredients with reduced paste viscosity and regulated paste stability under shear during heating.