39B-29

A. F. TRAPPEY¹, W. Prinyawiwatkul¹, P. W. Wilson², C. E. Johnson², and D. L. Park¹. (1) Department of Food Science, Louisiana State University Agricultural Center, Louisiana Agricultural Experiment Station, Baton Rouge, LA 70803, (2) Department of Horticulture, Louisiana State University Agricultural Center

Mayhaw fruit is not desirable for consuming raw due to its intense tartness and has been traditionally used in the Southeastern U.S. for small-scale production of home-made jams, jellies, and gourmet syrups. Knowledge of extraction techniques and their effects on quality of Mayhaw juice is lacking, thus merits investigation. Our objective was to evaluate physico-chemical properties and yield of Mayhaw juice from fresh vs. frozen fruits affected by different processing protocols. Fresh (1999 crop) and frozen (1998 crop) Mayhaw fruits (cv. Texas Star) were investigated. Four extraction methods were: steam extractions using whole fruits with added pulp (SEP) or without added pulp (SE), and cold-press extractions using whole fruits (CPE) or finely ground fruits (CPEG). Yield, acid and sugar contents, soluble solid, pH, titratable acidity (TA), and CIE-L*a*b*color of juices were determined. Three experimental batches were performed. The SE method gave higher yield than the CPE and CPEG methods, particularly for fresh fruits. The SEP method incorporated recoverable pulp after steam extraction into the extracted juice causing yield to increase from ca. 59% to 81% and 70%, respectively, for frozen and fresh fruits. Fructose and glucose are predominant sugars and malic acid is the predominant acid in extracted juices. Although giving higher juice yield, steam extractions yielded lower concentrations of malic/citric acids and fructose/glucose than cold extractions. TA but not pH (2.93-3.13) of extracted juices was significantly (p ³ 0.05) affected by extraction methods. The highest TA was observed for juice from the CPE method and the lowest from the SE method. Fresh fruits yielded juices with more intense redness and yellowness than frozen fruits, except for the CPEG method. Color lightness (L*) of juices was not affected by extraction methods. The unique color and flavor characteristics of Mayhaw juice may offer a novel, natural and flavorful ingredient for new product development.