Sorbic Acid as a Fungistatic Agent for Foods. Ix. Physico‐chemical Considerations in Using Sorbic Acid to Protect Foods

Abstract

In preceding papers it was shown that sorbic acid is an effective nontoxic and practical fungistatic agent for foods. Indeed it is unique among food additives, being a metabolizable food (3, 4 ) added for protective purposes t o another food. The published reports have dealt with the use of sorbic acid to inhibit mold spoilage in cheese. For a review of the earlier developments in four different laboratories, reference is made to the Smith and Rollin summary paper ( I d ) . EXPERIMENTAL PARTIn investigating the application of sorbic acid to other food products, a number of physio-chemical studies were carried out to obtain basic information of value in supplementing foods with this fungistatic agent. Earlier studies in this field have dealt with the spectrophotometric determination of sorbic acid in foods (5, 6) and on wrappers (6), the degrees of resistance to oxidative deterioration of sorbic acid as such, on wrappers, and in foods (8), and the importance of maintaining an adequately high ratio of sorbic acid to mold concentration (9). Additional basic information, accumulated since the earlier investigations, is now being reported. Purity of Commercially Available Sorbic AcidStudies were conducted on ten lots of commercially available sorbic acid" to determine the purity of the material available to investigators for use in both laboratory and plant studies, Most analyses were conducted on the materials as receivedb but with results expressed on a moisture-free basis.Melting point values were obtained on the sorbic acid samples after drying for 4 hours at 50°C. in a vacuum oven at 20 mm. (Hg) pressure.I n determining equivalent weight the sorbic acid was dissolved in neutral isopropanol and then titrated with 0.1 N sodium hydroxide solution to the first end-point with phenolphthalein as the indicator. Sorbic acid concentrations were calculated from the found equivalent weights using 112.12 as the theoretical for pure moisture-free sorbic acid. The ultra-violet * These samples were selected at random from aliquots of production lots retained by Carbide and Carbon Chemicals Company, New York. Sorbic acid loses moisture very rapidly during weighings at room temperature.For this reason, glass stoppered weighing bottles were employed in taking samples for analyses. 639

Modelling bacterial spoilage in cold-filled ready to drink beverages by Acinetobacter calcoaceticus and Gluconobacter oxydans

“…The parameter estimate was positive (Table 2), indicating that there was a synergy between pH and potassium sorbate. This combination is easily understandable, as organic acids such as sorbic acid and benzoic acid are more bactericidal in their undissociated forms, which are more prevalent at lower pH values (Eklund 1983; Chipley 1993; Davidson 1997), and this interaction is consistent with the literature (Gooding et al . 1955; Bell et al .…”

“…There was a synergistic effect between potassium sorbate and °Brix in the model ( P < 0·0094). Sugars can act synergistically with potassium sorbate to inhibit microbial growth (Gooding et al . 1955) and solutes generally increase the inhibitory action of potassium sorbate by increasing the concentration of undissociated sorbic acid (Sofos and Busta 1993).…”

Spectrophotometric Determination of Sorbic Acid in Apple Cidera

“…Commercial samples of sorbic acid and potassium sorbate from Union Carbide Chemicals Company were used (mention of companies or products does not imply endorsement by the United States Department of Agriculture over others not named). Ultraviolet absorption curves for carefully prepared solutions of known concentrations agreed with the published spectra of Alterton and Lewis (1958), Luckmann and Melnick (1955), and Melnick and Luckmann (1954).…”

SORBIC ACID AS A FUNGISTATIC AGENT FOR FOODS XI. EFFECTIVENESS OF SORBIC ACID IN PROTECTING CAKESa

“…The mechanisms by which sorbic acid inhibits mold growth have also been intensively explored (16,8,9). I n addition to the demonstrations that sorbic acid is of value in protecting cheese (22,23), margarine (20), fish ( 3 ) , pickles (18,10,5,2,21), gum and sugar solutions (19), citrus products ( l 7 ) , and fruit purees ( I ) against yeast and mold spoilage, the use of sorbic acid on an expanding commercial scale for the protection of other food products (4) including chocolate syrups, refrigerated fresh fruit salads, potato salads, and cold slaw attests to the effectiveness of sorbic acid in protecting foods in general.…”