Enhanced extraction of soluble dietary fibre and seed oil from tomato pomace

This paper reports the extraction of soluble dietary fibre (SDF) and seed oil, from tomato peel and seed respectively. SDF was extracted using the alkaline extraction method, while the oil was extracted by a surfactant-assisted aqueous extraction method (SAAE). The alkaline extraction method reported for papaya peels is optimised in the present work for tomato peels. Maximum SDF yield of 17.2 g/ 100 g of defatted peel was achieved with the following extraction conditions: NaOH 1% (w/w); temperature 50°C; solid/liquid (L/S) 50:1 and time 60 min. Extracted SDF showed a low molar mass of 1.27×106 Da which is desirable as it helps in the formation of a gel. For SAAE, surfactants were screened from a range of surfactants (L61, L62, L64, Tween 80, and Triton X-100). Out of these, L62, at 1% (v/v) concentration showed 70% (w/w) extraction yield in a single-stage extraction with a L/S ratio of 25:1. SDF and oil yield obtained from these methods were higher than previously reported extraction techniques. Thus, both the alkaline extraction and SAAE were found to be better methods for SDF and seed oil extraction respectively.