Application of response surface methodology in the formulation of spreadable creams from beechnut seeds as sustainable ingredient

Plants available in the spontaneous flora are recently studied as ingredients for food formulation in response to the demands for sustainable plant-based foods. The aim of this study was to obtain a new assortment of spreadable creams, free of palm oil, with good textural, rheological and colour attributes, high antioxidant activity and low cytotoxicity, from Fagus Sylvatica L. (European beech) seeds. A Box-Behnken design was used in order to find an optimal formulation based on textural, rheological, colorimetry, total polyphenolic content (TPC), antioxidant activity and cytotoxicity. Analysis of variance demonstrates that (i) the texture and (ii) rheology of the products are influenced by roasting temperature and sugar concentration, texture by the interaction of roasting temperature and duration, while rheological parameters by their interaction and squares, at a confidence level of at least p = 90%, (iii) whiteness index by each numeric factor, (iv) TPC by roasting duration, while antioxidant activity by the sugar content. Cytotoxicity (v) was expressed as a measure of cell viability under the application of 20 yl acidic extract of beechnut spreads and it was influenced by temperature, duration and their interaction. Optimization studies were based on the process sustainability and the product quality parameters achievement. Fourier transform infrared spectra revealed some differences due to the sugar addition, but not due to roasting at different temperatures (125-145-165 °C). The spreads with 20% sugar are similar in terms of textural, colour and rheological attributes to those with no sugar. Highest TPC and antioxidant activity are reached at 35 min of roasting, while 125 °C protocol is leading to increased toxicity levels. The forest seeds are a viable sustainable ingredient for novel spreads.