Comparison of microwave and conventional heating on physicochemical properties and phenolic profiles of purple sweetpotato and wheat flours

Effects of microwave energy transfer on release and degradation of anthocyanins in berry puree

To elucidate the distinctive effects of microwave energy on the anthocyanins content in berry puree, comparative experiments and simulation analysis of essentially heating modes are introduced via radiation (microwave), convective and conductive. Microwave energy has the strongest action on anthocyanins state due to uniform generation of in situ heating through entire volume of berry puree. Microwave heating may promote the release or hinder the degradation of anthocyanins as variable polar response and reaction barrier of anthocyanins depending on electric field direction with the unsymmetrical structure in polar molecules. The intermolecular force (hydrogen bond, van der Waals force etc.) may be broken in berry puree to form order arrangements of anthocyanins till tolerance temperature 80 °C under microwave heating. The optimal parameters of microwave heating are developed as microwave intensity of 30 W·g-1 and temperature of 50 °C to achieve the highest anthocyanins retention till target moisture less than 0.5 (d.b.).

Starch Modification with Molecular Transformation, Physicochemical Characteristics, and Industrial Usability: A State-of-the-Art Review

Starch is a readily available and abundant source of biological raw materials and is widely used in the food, medical, and textile industries. However, native starch with insufficient functionality limits its utilization in the above applications; therefore, it is modified through various physical, chemical, enzymatic, genetic and multiple modifications. This review summarized the relationship between structural changes and functional properties of starch subjected to different modified methods, including hydrothermal treatment, microwave, pre-gelatinization, ball milling, ultrasonication, radiation, high hydrostatic pressure, supercritical CO₂, oxidation, etherification, esterification, acid hydrolysis, enzymatic modification, genetic modification, and their combined modifications. A better understanding of these features has the potential to lead to starch-based products with targeted structures and optimized properties for specific applications.

Microwave-Induced Behavior and Digestive Properties of the Lotus Seed Starch-Chlorogenic Acid Complex

The effect of chlorogenic acid (CA) on the dielectric response of lotus seed starch (LS) after microwave treatment, the behavior and digestive characteristics of the resulting starch/chlorogenic acid complex (LS-CA) at different degrees of gelatinization and the inhibition of α-amylase by chlorogenic acid were investigated. The variation in dielectric loss factor, ε″, and dielectric loss tangent, tanδε, of the microwave thermal conversion indicated that LS-CA had a more efficient microwave-energy-to-thermal-energy conversion efficiency than LS. This gelatinized LS-CA to a greater extent at any given temperature between 65 and 85 °C than LS, and it accelerated the degradation of the starch crystalline structure. The greater disruption of the crystal structure decreased the bound water content and increased the thermal stability of LS-CA compared to LS. The simulated in vitro digestion found that the presence of the LS-CA complex improved the slow-digestion property of lotus seed starch by increasing its content of resistant and slowly digested starch. In addition, the release of chlorogenic acid during α-amylase hydrolysis further slowed starch digestion by inhibiting α-amylase activity. These findings provide a foundation for understanding the correlation between the complex behavior and digestive properties of naturally polyphenol-rich, starch-based foods, such as LS, under microwave treatment, which will facilitate the development of starch-based foods with tailored digestion rates, lower final degrees of hydrolysis and glycemic indices.

Factors influencing the starch digestibility of starchy foods: A review

Starchy foods are a major energy source of the human diet, their digestion is closely related to human health. Most foods require lots of processing before eating, therefore, many factors can influence starch digestibility. The factors that affect the digestibility of starches have been widely discussed previously, but the extracted starches in those studies were different from those present within the actual food matrix. This review summarizes the factors influencing the starch digestibility in starchy foods. Endogenous non-starch components hinder the starch digestive process. Food ingredients and additives decrease starch digestibility by inhibiting the activity of digestive enzymes or hindering the contact between starch and enzymes. Storage induce the retrogradation of starch, decreasing the digestibility of foods. Therefore, preparing starchy foods with whole grains, processing them as little as possible, using food additives reasonably, and storage conditions may all be beneficial measures for the production of low GI foods.

Effects of drying methods on bioactive components of Ganoderma lucidum fermented whole wheat in products & in vitro digestive model

The content of bioactive components is the key to determining the quality of Ganoderma lucidum fermented whole wheat (GW) products, and drying is a necessary link in the initial processing of GW, which will affect the bioactivity and quality of GW. This paper was to assess the effect of hot air drying (AD), freeze drying (FD), vacuum drying (VD) and microwave drying (MVD) on the content of bioactive substances and the characteristics of digestion and absorption of GW. The results showed that FD, VD and AD were beneficial to the retention of unstable substances such as adenosine, polysaccharide and triterpenoid active components in GW, and their contents were 3.84-4.66 times, 2.36-2.83 times and 1.15-1.22 times of MVD, respectively. The bioactive substances in GW were released during digestion. The bioavailability of polysaccharides in the MVD group (419.91 %) was significantly higher than that in the FD, VD and AD groups (68.74 %-78.92 %), but their bioaccessibility (5.66 %) was lower than that in the FD, VD and AD groups (33.41 %-49.69 %). Principal component analysis (PCA) showed that VD is more suitable for GW drying due to the comprehensive performance of 3 aspects in terms of active substance retention, bioavailability and sensory quality.

Effects of Reheating Methods on Rheological and Textural Characteristics of Rice Starch with Different Gelatinization Degrees

Pregelatinized starch (PGS) is often used to improve the processing quality of foodstuffs, but little attention has been paid to the effects of different reheating methods and degree of starch gelatinization (DSG) on their rheological and textural properties. In this study, pregelatinized rice starches (RS) with gelatinization degrees ranging from 58% to 100% were prepared via different Rapid Visco Analyser (RVA) heating procedures and reheated in various methods, including high-power microwave (HM), low-power microwave (LM), and water bath. The rheological behavior and textural properties were explored, and the results demonstrated that the consistency, gel strength, hardness, and springiness of PGS in all tested samples decreased significantly after reheating. The storage modulus (G') of PGS increased dramatically while the thermal stability decreased. Interestingly, the reheating methods possessed various effects on the starch of different DSG.