Effect of heat processing on phenolics and their possible transformation in low-sugar high-moisture (LSHM) fruit products from Kainth (Pyrus pashia Buch.-ham ex D. Don) fruit

Strategy for Enhancing Wheat Drying Efficiency and Flour Quality: Hybridization of Tempering and Hot Air Drying

The moderate processing of wheat is increasingly valued. One of the technological means to achieve moderate processing is the hybridization of tempering and hot air drying for postharvest wheat. The initial moisture content at onset of tempering (IMCOT) of wheat significantly influences the efficiency of hot air drying as well as the yield and quality of wheat flour. This study investigates the effects of varying IMCOT and tempering durations on the drying characteristics of wheat, the flour yield, the flour properties, and the properties of flour slurries. The findings revealed that tempering treatments reduced the drying time and altered the pasting characteristics of the flour slurries. This phenomenon could be attributed to the alteration of the kernel structure and starch destruction caused by tempering treatment. Tempering significantly (P < 0.05) affected the protein content and wet gluten content of wheat flour (WF). For the effect of IMCOT, the shortest drying time (35 min) was observed at an IMCOT of 0.17 g/g d.b., while the highest wet gluten content of WF was achieved when it was 0.19 g/g d.b. The lowest breakdown value (908.00 Brabender Units, BU) and highest setback value (811.50 BU) of WF were observed at an IMCOT of 0.19 g/g d.b. For the effect of tempering duration, the shortest drying time (35 min) was achieved at a tempering duration of 40 min. Tempering duration improved the whiteness and brightness of the flour, as well as increased its protein content. Considering the drying efficiency and the quality attribute, the optimal tempering condition was the IMCOT of 0.19 g/g d.b. and a tempering duration of 40 min.

Process Modeling and Convective Drying Optimization of Raspberry Pomace as a Fiber-Rich Functional Ingredient: Effect on Techno-Functional and Bioactive Properties

This study aimed to transform raspberry pomace, a by-product of the berry industry, into a sustainable, fiber-rich functional ingredient using convective drying. Drying experiments were conducted at temperatures of 50, 60, 70, 80, and 90 °C to identify the optimal conditions that balance process efficiency and preservation of functional and bioactive properties. The best results were achieved at 70 °C, where a high drying rate (DR) of 0.46 kg H2O·kg-1 db·min-1, effective moisture diffusivity (Deff) of 1.53 × 10-10 m2·s-1, and activation energy (Ea) of 34.90 kJ·mol-1 were observed. The Page model accurately represented the drying behavior (R2 = 0.9965-0.9997). Total dietary fiber (TDF) content remained stable across temperatures (52.52-64.76 g·100 g-1 db), while soluble dietary fiber (SDF) increased by 43.40%, resulting in a solubility (SOL) of 71.8%, water-holding capacity (WHC) of 8.2 mL·g-1 db, and oil-holding capacity (OHC) of 3.0 mL·g-1 db. High retention of bioactive compounds was achieved at 70 °C, including phenolics (32.10 mg GAE·g-1 db) and anthocyanins (25.84 mg C3G·g-1 db), resulting in significant antioxidant activities (DPPH: 33.29 mg AAE·g-1 db, IC50 0.016 mg·mL-1; ABTS: 35.85 mg AAE·g-1 db, IC50 0.029 mg·mL-1). These findings demonstrated the potential of convective drying at 70 °C to efficiently transform raspberry pomace into a high-quality functional ingredient. This process promotes sustainable production and waste reduction in the berry industry.

Quality Evaluation of Polygonatum cyrtonema Hua Based on UPLC-Q-Exactive Orbitrap MS and Electronic Sensory Techniques with Different Numbers of Steaming Cycles

In this study, electronic sensory techniques were employed to comprehensively evaluate the organoleptic quality, chemical composition and content change rules for Polygonatum cyrtonema Hua (PCH) during the steaming process. The results were subjected to hierarchical cluster analysis (HCA), principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). These analyses revealed, from a sensory product perspective, overall differences in colour, odour and taste among the samples of PCH with different numbers of steaming cycles. Using the UPLC-Q-Exactive Orbitrap MS technique, 64 chemical components, including polysaccharides, organic acids, saponins and amino acids were detected in PCH before and after steaming. The sensory traits were then correlated with the chemical composition. From the perspectives of sensory traits, chemical composition, and multi-component index content, it was preliminarily deduced that carrying out five cycles of steaming and sun-drying was optimal, providing evidence for the quality evaluation of PCH during the steaming process.

Changes in polyphenolic compounds and antioxidant activities of seed-used pumpkin during hydrothermal treatment

An environmentally friendly physical processing method, hydrothermal treatment (HT), was used to increase the content of specific compounds and antioxidant activities of seed-used pumpkin byproducts. The influence of hydrothermal temperature (80 °C-160 °C) and time (30-150 min) on changes in polyphenols and antioxidation was evaluated. The results revealed that the maximum free polyphenol content (140 °C for 120 min) was 3.96-fold higher than the untreated samples. Elevated temperature and long duration changed phenolic acid contents. For example, p-coumaric acid, rutin and chlorogenic acid exhibited a decreasing trend, and p-hydroxybenzoic acid, quercetin and cinnamic acid showed an increasing trend. Compared to controls, HT was significantly associated with increased antioxidant activities. To comprehensively reveal the influence of hydrothermal temperature and time on changes in polyphenolic content, back propagation artificial neural network (BP-ANN) models with accurate prediction ability were developed, and the results exhibited well-fitted and strong approximation ability (R² > 0.95 and RMSE < 2 %) and stability.

Hot Air Drying of Seabuckthorn (Hippophae rhamnoides L.) Berries: Effects of Different Pretreatment Methods on Drying Characteristics and Quality Attributes

Seabuckthorn berries are difficult to dry because the outermost surface is covered with a dense wax layer, which prevents moisture transfer during the drying process. In this study, uses of ultrasonic-assisted alkali (UA), pricking holes in the skin (PH) and their combination (UA + PH) as pretreatment methods prior to hot air drying and their effects on drying characteristics and quality attributes of seabuckthorn berries were investigated. Selected properties include color, microstructure, rehydration capacity, as well as total flavonoids, phenolics and ascorbic acid contents. Finally, the coefficient of variation method was used for comprehensive evaluation. The results showed that all pretreatment methods increased the drying rate; the combination of ultrasonic-assisted alkali (time, 15 min) and pricking holes (number, 6) (UA15 + PH6) had the highest drying rate that compared with the control group, the drying time was shortened by 33.05%; scanning electron microscopy images revealed that the pretreatment of UA could dissolve the wax layer of seabuckthorn berries, helped to form micropores, which promoted the process of water migration. All the pretreatments reduced the color difference and increased the lightness. The PH3 samples had the highest value of vitamin C content (54.71 mg/100 g), the UA5 and PH1 samples had the highest value of total flavonoid content (11.41 mg/g) and total phenolic content (14.20 mg/g), respectively. Compared to other pretreatment groups, UA15 + PH6 achieved the highest quality comprehensive score (1.013). Results indicate that UA15 + PH6 treatment is the most appropriate pretreatment method for improving the drying characteristics and quality attributes of seabuckthorn berries.