Characteristics of the raw fruit, industrial pulp, and commercial jam elaborated with Spanish quince (Cydonia oblonga Miller)

Abstract

Quince fruit and two industrial derivates (pulp and jam) were characterized from physicochemical, nutritional and microbiological viewpoint. Quinces were collected at maturity (September) in Murcia (Spain). Quinces were converted at a processing factory in pulp (intermediate product) and, in the same factory, this pulp was transformed in jam. The pH, soluble solids, acidity, color, moisture, water activity, total phenolic compounds, antioxidant activity, vitamin C and flavonoids were measured for all samples, while for microbiological analysis was only used quince jam. There were significant differences among quince fruit, industrial pulp and commercial jam. Processing caused pH, moisture and water activity decrease, while soluble solids increase. Total phenolic compounds and antioxidant activity increased in the pulp and in the jam. The effect of cooking and storage was a decrease of vitamin C and flavonoids in the jam. Quince jam presented a total number of molds and yeasts lower than 2 log cfu/g. Although the production parameters affect to the quality of the quince jam, it is a sensory attractive food with healthy properties.