Relationships between Hydrocolloid Coating and Mushroom Structure

Abstract

Agaricus bisporus edible mushrooms were coated with different gum-based coatings, including alginate and alginate−ergosterol, with or without emulsifier. The structures of the different parts of the mushroom tissue were studied by SEM. Various penetration modes of coating and cross-linking solutions into the tissue were examined. The techniques of ICP and X-ray analysis were used to quantify the presence and depth of penetration of minerals into the mushroom tissue before and after coating. Critical surface tension of the “solid” upper surface of the mushroom was estimated using the Zisman plot. The alginate-based coating solutions were tested for their surface tension and contact angles on the mushroom tissue. Reduction in the surface tension and the contact angles of the coating solutions lead to better wettability of the surface. Coated mushrooms were found to have a better appearance, a better color, and an advantage in weight in comparison with the uncoated ones. The alginate−ergosterol−Tween coating combination was most suitable for maintaining the size and shape of the coated mushroom. Keywords: Coating; hydrocolloid; mushroom; penetration; surface tension

Effect of Edible Coatings Containing Soy Protein Isolate (SPI) on the Browning and Moisture Content of Cut Fruit and Vegetables

“…Adding calcium salts to soy-protein coatings may control darkening of fruits and vegetables [Park et al, 2001]. A previous report showed that alginate-based coating solution, a carbohydrate having a carboxylic group, was effective in maintaining the better appearance and color of the mushroom for a long period [Hershko and Nussinovitch, 1998]. …”

Chitosan-Based Edible Films

“…Alginate coatings are good oxygen barriers that can retard lipid oxidation in various fruits and vegetables and have been found to reduce weight loss and natural microflora counts in minimally processed carrots (Amanatidou et al 2000). Calcium alginate coatings were found to improve the quality of fruits and vegetables, such as reducing shrinkage, oxidative rancidity, moisture migration, oil absorption, and sealing in volatile flavors, improving appearance and color and reducing weight loss of fresh mushrooms in comparison with uncoated ones (Hershko and Nussinovitch 1998).…”

Innovations in the Development and Application of Edible Coatings for Fresh and Minimally Processed Fruits and Vegetables

“…Alginate coatings are good oxygen barriers (Conca and Yang 1993) that can retard lipid oxidation in various fruits and vegetables (Kester and Fennema 1986), and have been found to reduce weight loss and natural microflora counts in minimally processed carrots (Amanatidou and others 2000). Calciumalginate coatings were found to improve the quality of fruits and vegetables, such as reducing shrinkage, oxidative rancidity, moisture migration, oil absorption, and sealing-in volatile flavors, improving appearance and color, and reducing weight loss of fresh mushrooms in comparison with uncoated ones (Hershko and Nussinovitch 1998).…”