Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2001
Publication Date: N/A
Interpretive Summary: In the last few years, strawberries have remained the largest single berry crop in the State of Oregon. As of February 2000, 41,600 million lbs were harvested and 96% of the total production (39,900 lbs) was utilized by the food industry. When strawberries are processed into juice and concentrate, there is marked destruction of pigments, which subsequently continues during storage. The pigment degradation in strawberry products has been of concern to growers and food processors since the red color of the fresh fruit changes into a brown pigment. This appears to the consumer as an indicator of inferior quality and deterioration of the fruit. This investigation demonstrated that the rate of pigment is higher in strawberry concentrate as compared to strawberry juice. Increasing total pigment concentration enhances stability and delays the color change. These results will benefit strawberry producers and processors by providing a method to increase the color shelf life in both strawberry juice and concentrate.
Technical Abstract: Strawberries were processed into juice (8 deg brix) and concentrate (65 deg brix) and different lots were fortified with pelargonidin 3-glucoside, pelargonidin 3-sophoroside, and acylated pelargonidin 3-sophoroside 5-glucoside. Changes in pigment composition, color (CIE L*a*b*), and ascorbic acid content were monitored during storage at 25 deg C. Anthocyanin and ascorbic acid degradation followed first order kinetics. Fortification increased the half life of the pigments from 3.5 to 5 days in concentrate and from 5 to 12 days in juice. The half-life of ascorbic acid was 2 days in juice samples and ranged from 3 to 10 days in concentrate samples. Both systems showed changes in chroma and hue angle, but maintained L* values.