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United States Department of Agriculture

Agricultural Research Service

Title: The value of acidic-electrolyzed water for stabilizing salmon by-products

Author
item Bower, Cynthia

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: February 20, 2007
Publication Date: N/A

Interpretive Summary: By-products from Alaska’s fishing industry represent an underutilized resource, which is often treated as waste. These high-protein discards can be preserved as fishmeal, or (less commonly) through ensilage or fermentation. Electrolyzed water produces an acidic component with a high oxidation-reduction potential capable of decreasing bacterial numbers. The objective of this study was to evaluate the efficacy of acidic-electrolyzed water for stabilizing salmon by-products. Exploration of new preservation methods, such as acidic-electrolyzed water, is needed to increase utilization and offset environmental impact caused by disposal of food processing wastes.

Technical Abstract: Alaska’s fishing industry generates over one million metric tons of fish by-products each year, much of which is discarded during processing unless fishmeal plants are located nearby. Other preservation methods, such as ensilage and fermentation, are less common, but can acidify perishable by-products to inhibit growth of spoilage bacteria. Electrolyzed water produces an acidic component with a high oxidation-reduction potential capable of decreasing bacterial numbers. The objective of this study was to evaluate the efficacy of acidic-electrolyzed water for stabilizing salmon by-products. Pink salmon (Oncorhynchus gorbuscha) heads, viscera, and head-viscera mixtures were homogenized with 2.5% NaCl. Acidic-electrolyzed water (pH 2.85; ORP 1100 mV) was applied directly to head and viscera samples, and was also used as a pre-wash for salmon heads to reduce the bacterial load. Containers were held at 21°C and sampled at 30, 60, and 120-days to determine percent liquefaction, compositional analyses (moisture, ash, protein, and lipids), soluble nitrogen, pH, bacterial counts (total CFU/g, lactic acid bacteria, and coliforms), and chemical analyses (ammonia and lactic acid levels). Results were compared with other stabilization procedures including direct acidification (ensilage using 1% formic acid or 2% phosphoric acid), acidification through lactic acid bacteria (fermentation using six homofermentative strains and 15% sucrose), and combinations of both techniques. All silages and fermentates (except controls) stabilized at pH 4.5 or lower. Acidic-electrolyzed water, when used as a pre-wash in combination with lactic acid bacteria, inhibited growth of coliforms and mold, with pH and CFU/g similar to non-washed controls. However, direct addition of acidic-electrolyzed water required large volumes (10:1) to decrease fish homogenates below pH 4, and did not retain acidity beyond 48 hours. Exploration of new methods, such as acidic-electrolyzed water, for preserving food processing wastes is needed to increase utilization and offset environmental impact of excessive by-product disposal.

Last Modified: 12/18/2014
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