An update on the scientific evidence around nut processing, based on local and international published research papers.

Comparison of changes in sterol content of nuts after roasting using conventional and microwave methods and after storage. (Kulik et al, 2025).
The aim of this study was to determine the influence of the roasting process (conventional and microwave methods) and long-term storage (12 months) on phytosterol content of nuts (hazelnuts, walnuts, and shelled peanuts). In the studied nuts, five main types of phytosterols were identified: campesterol, stigmasterol, ß-sitosterol, delta 5-avenasterol and cycloartenol. Among the findings, roasting resulted in total sterol losses of 7.3 to 13.8%, with microwave roasting causing twice as much loss as conventional roasting. And the sterols contained in raw nuts were systematically lost over 12 months of storage. Depending on the type of nut, this ranged from about 6 to >20% of the initial amount.

Does ‘activating’ nuts affect nutrient bioavailability? (Kumari et al, 2020)
This study assessed the effects of different soaking regimes on phytate and mineral concentrations of whole and chopped almonds, hazelnuts, peanuts, and walnuts. The treatments were: 1. Raw; 2. soaked for 12 h in salt solution; 3. soaked for 4 h in salt solution; 4. soaked for 12 h in water. Although there were some statistically significant differences in phytate concentrations between treatments, no soaking treatment reduced phytate concentrations to a level that would result in clinically meaningful improvements in the bioavailability of minerals. In summary, the authors found no evidence that soaking is an effective strategy to reduce phytate concentrations and improve the nutrient bioavailability of almonds, hazelnuts, peanuts and walnuts.

The effects of ‘activating’ almonds on consumer acceptance and gastrointestinal tolerance. (Taylor et al, 2018).
In this 8-week randomised crossover trial, 76 participants were allocated 30 g/day of four different preparations of almonds for 12 days: whole unsoaked, whole soaked, sliced unsoaked, and sliced soaked. Ratings of overall liking, desire to consume, and likelihood of future consumption, and severity of gastrointestinal symptoms were measured daily. It found that nuts, including in different forms, had high acceptance ratings. They are also well tolerated gastrointestinally. And soaking (or activating) the almonds did not reduce phytate concentrations, nor did it improve gastrointestinal tolerance, compared with un-soaked nuts.