RSC Advances PAPER Application of soy protein coatings and their effect on the quality and shelf-life stability of beef patties Cite this: RSC Adv., 2015, 5, 8182
Pedro Guerrero,a Maurice G. O'Sullivan,b Joe P. Kerryb and Koro de la Caba*a The application of soy protein coating was found to be effective in delaying lipid oxidation and deterioration of beef patty quality during chilled storage. Protein-based edible coatings improved surface color stability of beef patties stored in modified atmosphere packaging (MAP). Additionally, texture profile analysis showed that textural parameters of soy protein-coated samples were maintained up to 14 days, in contrast to the Received 29th October 2014 Accepted 24th December 2014
deterioration observed for controls. Moreover, sensory analysis showed that consumers did not find any
DOI: 10.1039/c4ra13421d
application. Therefore, soy protein coatings prepared in this study extended shelf-life, offering an
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alternative edible coating for the preservation of fresh food.
negative effect on hedonic or intensity attributes associated with beef patty samples following coating
Introduction The research in edible lms and coatings to extend the shelf-life of food products has attracted increasing interest in recent years due to several factors such as consumer demand for high quality food,1 government demand for reducing packaging waste,2 and marketing demand for new products.3 Additionally, the food industry is constantly seeking new and improved packaging systems and materials in a further attempt to prevent deteriorative changes of food quality and consequently, extend food shelf-life.4 Oxidation processes account for some of the most signicant mechanisms which pertain to food spoilage. Lipid oxidation is one of the major limiting processes responsible for the reduction in food shelf-life, since it leads to off-avor, off-odor and has been linked to oxidation reactions that cause product discoloration.5 Synthetic antioxidants have been used to prevent lipid oxidation, but the increasing demand of natural products has renewed the interest in natural polymers as raw materials for edible coatings or lms due to their potential to extend shelf-life of food and reduce complexity and cost of packaging systems.6 Additionally, edible lms and coatings can improve sensory attributes like color, odor, and taste. The most important properties of food for consumers are appearance, texture, and avor. At the point of sale, the appearance is the most important factor, with a close link between this attribute and the decision to purchase.7 In the case of fresh meat, low storage temperatures combined with modied atmosphere packaging (MAP) are the preferred methods of preserving good appearance.8
a
BIOMAT Research Group, University of The Basque Country (UPV/EHU), Polytechnic School, Plaza Europa 1, 20018 Donostia-San Sebastian, Spain. E-mail: koro.
[email protected]; Tel: +34 943 017188
b
MAP consists in the removal and/or replacement of the atmosphere surrounding a product before sealing in gas-barrier materials. Oxygen (O2), carbon dioxide (CO2) and nitrogen (N2) or their mixtures are regularly used in MAP.9 Typically, modied atmosphere packs containing 80% O2 and 20% CO2 are used in retail beef markets as CO2 inhibits growth of spoilage bacteria, and O2 favors the bright red color of fresh beef, which is appealing to consumers.10 In freshly cut beef, myoglobin is in the form of deoxymyoglobin, which is purplish-red in color. Following exposure to air or high O2 levels, oxygenation of myoglobin results in the formation of oxymyoglobin, conferring a bright cherry-red color to fresh beef. At early stages of storage, O2 retards formation of metmyoglobin, which is brown in color and undesirable from a consumer viewpoint.11 However, high O2 level can also promote oxidation, particularly of lipids, and membrane phospholipids are particularly susceptible to oxidation processes that cause the development of meat rancidity. In this context, edible coatings and lms can act as O2 barriers and extend food shelf-life.12 They can be formed from proteins such as gelatin13 and soy protein,14 polysaccharides such as starch,15 agar,16 and chitosan,17–19 or proteinpolysaccharide blends.20,21 In the case of soy protein, it is extracted from soybeans used to obtain soy oil. During this process, soy our is obtained as a secondary product and it can be puried to obtain soy protein concentrate (SPC) and soy protein isolate (SPI), adding value to agricultural by-products.22 Additionally, soy proteins have the ability to form lms and coatings that show excellent functional properties and, among them, excellent O2 barrier.23,24 However, information on their application to foods is limited, thus the aim of this work was to investigate the effectiveness of soy protein-based edible coatings to maintain physicochemical properties of beef patties, extending the shelf-life of these fresh food products.
Food Packaging Research Group, University College Cork (UCC), Cork, Ireland
8182 | RSC Adv., 2015, 5, 8182–8189
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