Esther Vidal Cascales¹, María Isabel Alarcón Flores¹, Adriana Hurtado Gómez¹, Inés González Hidalgo¹, José María Ros García^1,

The purpose of this research is to evaluate the stability of the added fructooligosaccharides during the processing and the shelf life of an aseptically packed commercial pineapple nectar. With this objective, a pineapple nectar was produced in a fruit juices factory, being enriched in fructooligosaccharides (0.6%). The pineapple nectar was sterilized by heat and aseptically packed. The storage of the pineapple nectar was at room temperature. A sample of six bottles of nectar was taken before nectar processing and once packed, at time intervals during the one- year storage, also was taken a sample of six packs of nectar. The following analyses were carried-out: soluble solids, pH, turbidity, colour, content in fructooligosaccharides, sucrose, glucose and fructose, and microbiology. The results indicate that soluble solids, pH, turbidity and colour parameters keep constant during the processing and the storage. The microbiology of the packed nectar indicates the effectiveness of the thermal treatment. Fructooligosaccharides and sucrose are stable during the high temperature-short time thermal treatment and during the aseptic packaging, while they are instable during the storage. After one year, the concentration of fructooligosaccharides and sucrose was the 14% and 30% of the initial, respectively. Considering the instability of the fructooligosaccharides in acid medium, fruit beverages producers must adjust the initial content in order to keep some levels of fructooligosaccharides during the shelf life, even at its end. This result also suggests that fructooligosaccharides could be more adequate to enrich solid food than liquid food, if the shelf life is long.

fructooligosaccharides, sugars, shelf life, pineapple, nectar, aseptic packaging