Textural Changes in Mushrooms (Agaricus bisporus) Associated with Tissue Ultrastructure and Composition

Abstract

The objective of this study was to determine ultrastructural and compositional changes in fresh mushrooms associated with adverse changes in texture during 9 d of post-harvest storage at 12°C. Mushroom softening (2.6N to 1.5N, puncturing force) was consistent with toughening (19.2N to 33.0N, gumminess). Protein and total carbohydrate content declined, but chitin content increased during mushroom storage. Most polysaccharides were extracted after deacetylation and depolymerization of chitin, indicating that structural glucans were mainly bound with acetylglucosamine polymers. Softening paralleled expansion of intercellular space at the pilei surface, hyphae shrinkage, central vacuole disruption, and loss of proteins (r = 0.94) and polysaccharides (r = 0.84), while toughening was associated with increased chitin content (r = 0.95).

Gene expression and metabolite changes during Tuber magnatum fruiting body storage

“…These events are probably also present during the latter ripening stages. Zivanovic et al (2000) demonstrated that A. bisporus mushrooms simultaneously softened and toughened during post-harvest storage, and showed an increase in chitin content. The herein observed regulation of TmachsG, encoding a putative class III chitin synthase in less ripe fruiting bodies, is in agreement with previous data (Balestrini et al 2000), which demonstrated that TbCHS3 (a T. borchii class III chitin synthase) plays a role during spore cell wall formation, thus suggesting that spore maturation is still in progress.…”

Effects of Porosity and Thermal Treatment on Hydration of Mushrooms

“…During storage, mushrooms are still physiologically active and mature. Prolonged maturation has shown an increase in their hydration after a thermal treatment (Beelman, Kuhn, and McArdle 1973;Beelman and McArdle 1975;Zivanovic, Busher, and Kim 2000). While the reason for such an increase is attributed to the proteolytic changes in protein (Beelman, Kuhn, and McArdle 1973;Beelman and McArdle 1975), this paper gives the insight that maturation influences the hydration properties via porosity changes.…”

“…The change in the intercept with storage indicates that storage not only induces change in porosity but also induces other physiological changes in the gel phase of mushroom altering the hydration of stored mushroom. It is known in literature that the storage of mushroom brings about several biochemical changes in the gel phase of mushroom, including a decreased level of mannitol, total and soluble protein content, and glucan level and an increase in structural components chitin and cell wall proteins (Ajlouni et al 1995;Hammond and Hammond 1979;Hammond and Nichols 1975;Zivanovic et al 2000). In the fungal cell wall, chitin provides mechanical strength to the cell wall (Bowman and Free 2006;Zivanovic et al 2000).…”

“…6 The degree of hydration of heat-treated mushroom (90°C/15 min) plotted against their porosity for day zero (red square), one (green triangle), two (purple circle), and three (blue diamond). The open and closed symbols represent two different batches surface is reported to be more porous, having larger openings (Zivanovic et al 2000) with a lower density than the rest of the tissue (Schijvens et al 1996). The increased density at the surface in the stored mushroom might be due to surface drying of mushroom with storage days.…”

The effect of process parameters and microstructural changes on a new convenience food – quick-frozen paste-coated mushrooms (Agaricus bisporus)

“…The TEM studies showed the changes inside the dense structure of PCAB frozen at different temperatures and the results are explained below (Cole and Skellerup 1986;Zivanovic et al 2000).…”