Effects of Infrared Treatments on Some Constituents, Functional Properties and Mucilage Properties of Chia Seed

Abstract

Chia seed (Salvia hispanica) has high nutritional value and positive effect on health due to its protein and total dietary fiber contents, phenolic compounds, and essential oils. Mucilage extracted from chia can be used as a gelling agent, foaming agent, emulsifier, and coating material in food industry. In recent years, utilization of infrared (IR) treatment in food industry is increasing, due to its advantages (direct heat penetration, fast heating rate, short processing time, energy saving, low cost) over conventional heating. Infrared treatment has been used for drying (fruits, vegetables, grains etc.), cooking, roasting, thawing, sterilization, enzyme inactivation, and for enhancing the extraction of some bioactive compounds (polyphenols, flavonoids etc.). In literature, microwave, roasting, and autoclaving have been applied to chia seeds for various purposes such as extracting health beneficial components, increasing extraction efficiency or improving functional, and organoleptic properties and storage stability. To the best of our knowledge, in literature effects of infrared treatment on some constituents, functional properties, and mucilage properties of chia seed were not investigated. Therefore, in this study, chia seeds were infrared treated at different powers (700W, 900W and 1100W) and times (25 and 50min). The effects of infrared treatment on protein, ash, color, total dietary fiber, total phenolic content, total flavonoid content, phenolic profile (by HPLC), antioxidant activity (DPPH, TAC), FTIR spectrum, and functional properties (water and oil holding capacity, emulsion activity, and stability) of chia samples were investigated. Mucilage was extracted from control and infrared treated chia samples and mucilage properties were determined. The effects of infrared treatment on the yield, protein, ash, color, total dietary fiber, functional properties (water and oil holding capacity, emulsion activity, and stability, viscosity) and FTIR spectrum of mucilage samples were investigated. In the present study, infrared treatment caused increases in total phenolic content, total flavonoid content (except 1100W), antioxidant activity, chlorogenic acid, rutin, ferulic acid (except 1100W-50 min), quercetin (except 700W-25 min, 900W-50 min and 1100W), emulsion activity (except 900W-50 min and 1100W), emulsion stability (except 900W and 1100W), and total dietary fiber (except 1100W) of chia samples. Infrared treatment of chia samples resulted in significant increases in yield, emulsion activity (at 700W and 900W), and emulsion stability (at 700W and 900W) of mucilage samples. Infrared treatment of chia samples at all powers and times caused a negative effect on water and oil holding capacities of chia and mucilage samples. FTIR spectrums for infrared treated chia samples and mucilage samples extracted from these chia samples have all the specific peaks reported in literature. Infrared treatment of chia samples only at 900W-50min and 1100W-50min resulted in lower viscosity values for mucilage samples (1% and 2%, w/v). For food industry, utilization of infrared treated chia is promising as a high value raw material due to its high amount of health beneficial constituents. Mucilage extracted from chia seeds takes part in many industrial applications (food, chemistry, etc.). Infrared treatment of chia seeds is also promising in terms of increased mucilage yield and improved some mucilage properties.