How does water stress and roasting temperature affect the physicochemical parameters of almonds?

Abstract

Regulated deficit irrigation (RDI) is a useful strategy to reduce the water consumption maintaining the fruit quality. The almonds cultivated under RDI conditions are called hydroSOStainable because are produced under environmentally friendly conditions and present an improved quality. It was demonstrated that almond cultivar and agronomical practices, can affect the kernel chemical composition and consequently the parameters for the roasting process of almonds. The influence of three roasting temperatures (150 ◦C, 170 ◦C and 190 ◦C) on the quality of almonds belonging to 2 irrigation treatments (T1: control and T2: hydroSOStainable almonds) was evaluated. For this, moisture, water activity (aw), organic acids, sugars, antioxidant activity (AA), total phenolic content (TPC) and fatty acids content were measured. Results showed that moisture content, aw, AA (ABTS•+ and DPPH• ), and polyunsaturated fatty acids (PUFAs) were reduced with the most severe roasting treatment. While citric, isobutyric, maltoheptaose and maltotriose content was increased. HydroSOStainable almonds had significantly higher content of AA, TPC, organic acids, sugars, PUFAs and total fatty acids than control almonds; this tendency was present at 170 ◦C, but not at 190 ◦C. Consequently, 170 ◦C during 10 min was the recommended roasting conditions for the hydroSOStainable almonds.