Browsing by Author "Lu W"

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    Heat-induced modifications of pea protein: Implications for solubility and digestion behaviour
    (Elsevier B.V., 2025-08-20) Li D; Ma Y; Acevedo-Fani A; Lu W; Singh H; Ye A
    Plant proteins have become increasingly desirable due to their sustainability and proposed health benefits. This study initially examined the effects of heat treatment on the solubility of pea protein (PP) in a 3 % (w/w) protein solution, applying heat from 65 °C to 95 °C for varying durations across pH conditions ranging from 5.5 to 7.8. Subsequently, an advanced dynamic gastric digestion model—the Human Gastric Simulator—was employed to examine the in vitro gastric digestion behaviours of heat-treated and untreated PP. Results suggest that heat treatment reduces the protein aggregate size and enhances PP solubility, potentially due to a decrease in α-helix and β-turn structures or an increase in β-sheet content, as determined via Fourier transform infrared spectroscopy. Additionally, heat treatment elevated the surface hydrophobicity and free sulfhydryl group concentration of PP. During in vitro dynamic gastric digestion with pepsin, PP underwent notable structural and physical stability modifications. Unheated and heated PP exhibited small particles in the digesta and remained unaggregated throughout digestion. However, the heat-treated PP showed a smaller particle size during gastric digestion and a greater hydrolysis rate than the unheated protein. This study systematically evaluates the solubility and digestion behaviour of PP subjected to food processing conditions, highlighting its stability and structural changes that may influence the delivery of macronutrients from the stomach to the next phase of digestion.
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    Pathogenicity of Beauveria bassiana PfBb and Immune Responses of a Non-Target Host, Spodoptera frugiperda (Lepidoptera: Noctuidae)
    (MDPI AG, 8/10/2022) Gao Y-P; Luo M; Wang X-Y; He X; Lu W; Zheng X-L
    Exploring the pathogenicity of a new fungus strain to non-target host pests can provide essential information on a large scale for potential application in pest control. In this study, we tested the pathogenicity of Beauveria bassiana PfBb on the important agricultural pest Spodoptera frugiperda (Lepidoptera: Noctuidae) by determining the relative activities of protective enzymes and detoxifying enzymes in different larval instars. Our results show that the B. bassiana PfBb strain could infect all six larval instars of S. frugiperda, and its virulence to S. frugiperda larvae gradually increased with an increase in spore concentration. Seven days after inoculation, the LC50 of B. bassiana PfBb was 7.7 × 105, 5.5 × 106, 2.2 × 107, 3.1 × 108, 9.6 × 108, and 2.5 × 1011 spores/mL for first to sixth instars of S. frugiperda, respectively, and the LC50 and LC90 of B. bassiana PfBb for each S. frugiperda instar decreased with infection time, indicating a significant dose effect. Furthermore, the virulence of B. bassiana PfBb to S. frugiperda larvae gradually decreased with an increase in larval instar. The activities of protective enzymes (i.e., catalase, peroxidase, and superoxide dismutase) and detoxifying enzymes (i.e., glutathione S-transferases, carboxylesterase, and cytochrome P450) in S. frugiperda larvae of the first three instars infected with B. bassiana PfBb changed significantly with infection time, but such variations were not obvious in the fifth and sixth instars. Additionally, after being infected with B. bassiana PfBb, the activities of protective enzymes and detoxification enzymes in S. frugiperda larvae usually lasted from 12 to 48 h, which was significantly longer than the control. These results indicate that the pathogenicity of B. bassiana PfBb on the non-target host S. frugiperda was significant but depended on the instar stage. Therefore, the findings of this study suggest that B. bassiana PfBb can be used as a bio-insecticide to control young larvae of S. frugiperda in an integrated pest management program.