Role and Function of Gels in Food Storage and Processing

Dear Colleagues,

With the increasing demand for high-quality fruits and vegetables, understanding gel formation mechanisms during storage and processing has become crucial for texture control and quality preservation. Gels derived from plant cell wall components, particularly pectin, play a vital role in determining the structural integrity, firmness and sensory attributes of fresh and processed produce. During fruit and vegetable ripening, storage and thermal processing, complex biochemical and physical changes occur, leading to gelation or the degradation of pectic polysaccharides. These gel-forming processes directly influence the texture, mouthfeel and overall acceptability of products such as jams, jellies, fruit fillings and canned vegetables. Moreover, factors such as pH, temperature, sugar content, calcium ions and endogenous enzymes (e.g., pectinmethylesterase, polygalacturonase) significantly affect the gelling behavior of pectin and other hydrocolloids. The molecular structure of pectin—including its degree of methoxylation, molecular weight, branchin, and neutral sugar side chains—determines its gelation mechanism (e.g., high-methoxyl vs. low-methoxyl pectin gels) and the resulting gel texture (e.g., strength, elasticity, syneresis). Therefore, a systematic understanding of gel formation in fruit and vegetable matrices is essential for optimizing processing conditions, improving product quality and developing novel gel-based food materials. This Special Issue aims to present the latest research, from both academics and industrial professionals, on gel formation mechanisms and texture control in fruits and vegetables during storage and processing. The key topics of this Special Issue include the following:

① Gel formation mechanisms in fruit and vegetable systems during storage and processing, including pectin gelation, enzyme-mediated gelation and interactions with other components (e.g., proteins, sugars, and minerals).

② Factors influencing gel formation, such as pH, temperature, sugar concentration, calcium ions, endogenous enzymes (e.g., pectinmethylesterase, polygalacturonase) and processing conditions (e.g., thermal, high-pressure, or ultrasound treatments).

③ Effects of gelation on fruit and vegetable texture, including changes in firmness, softening, tissue integrity, rheological properties and water-holding capacity during storage and processing.

④ The influence of pectin structure—degree of methoxylation, degree of acetylation, molecular weight, neutral sugar side chains (e.g., rhamnogalacturonan-I) and molar mass distribution—on gelation behavior, gel kinetics and final gel texture (e.g., strength, elasticity, brittleness and syneresis).

⑤ Advanced characterization techniques for gel structure and texture in fruit, such as atomic force microscopy (AFM), texture profile analysis (TPA), and low-field NMR (LF-NMR)

⑥ Applications in fruit and vegetable processing, including jam, jelly, fruit filling and texture-modified products, as well as strategies for texture preservation during extended storage (e.g., cold storage, controlled atmosphere or edible coatings).

Dr. Jianfen Ye
Prof. Dr. Xi Yang
Guest Editors

Manuscript Submission Information

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