Effect of hydrothermal and thermal processing on the antioxidative, antinutritional and functional characteristics of Salvia hispanica

Chia seeds (Salvia hispanica), owing to their nutritional quality are categorised as supergrains. These super grains were subjected to hydrothermal (boiling, autoclaving) and thermal (roasting, microwave) processes, and the influence of these processing conditions was assessed on antioxidant activities, bioactive compounds, anti-nutritional factors and functional characteristics. Results revealed that all processing treatments and their durations brought significant (p < 0.05) changes in quality characteristics of Salvia hispanica. Boiling (2 min) and microwave (5 min), significantly increased total phenolic content by 7.77 and 3.14%, FRAP by 11.14, 21.75%, and reducing power by 5.41 and 6.26% respectively, while autoclaving brought significant reduction. Roasting and microwave processing significantly reduced DPPH center dot and ABTS(center dot+)scavenging activities, whereas reducing power and metal chelating activities increased by 6.26 and 18.26%. All thermal processes significantly reduced phytates (29.7-49.9%) and saponins (9.9-62.3%), whereas tannin contents increased (8.3-96.5%) especially during boiling, although the antinutrients were within safe limits. All treatments significantly enhanced oil absorption (29.7-49.9%) and flour dispersibility (9.9-62.3%) of chia seeds while, water absorption capacity and swelling power increased respectively by 15.16 and 6.09% after roasting (2 min) and, by14.24 and 10.14% after microwave processing (2 min). Water solubility index and swelling solubility decreased by 33.71-56.7% and 13.39-45.76% respectively, while the processed chia seeds showed diminished emulsifying properties. These results suggested that thermal and hydrothermal processing could be utilized to provide optimal balance of enhanced antioxidative and functional properties with reduction of antinutrients to approve regular consumption of chia seeds.

Automated summary

The study found that different thermal and hydrothermal processing of chia seeds significantly affected their quality characteristics, increasing antioxidant activities and functional properties while reducing anti-nutritional factors, making them more suitable for regular consumption.