385: Developing High-Value Food Ingredients From Purple Sweet Potatoes Using Supercritical Carbon Dioxide-Based Green Approaches

Introduction

The growing consumer preference for healthier and environmentally sustainable food products has driven the food industry to seek natural alternatives to synthetic additives. Among these additives, synthetic colorants have been a focus of concern due to their potential health risks. PSP is a rich source of anthocyanins that are responsible for their color and health benefits. However, these anthocyanins are prone to oxidation. Therefore, anthocyanins were extracted from PSP using an environmentally friendly approach based on SC-CO2, and the spent PSP was used to develop nanoporous aerogels to encapsulate anthocyanins.

Methods

The cosolvent-modified SC-CO2 conditions (temperature (35-55°C), pressure (30-40 MPa), and cosolvent concentration (10-30%) were optimized to maximize the anthocyanins’ extraction. Next, aerogels were prepared using PSP (0, 5, 10, 15, and 20%, w/w) combined with corn starch and spent PSP (0, 5, 10, and 15%, w/w) via SC-CO2 drying. The extracts and aerogels were characterized for their total phenolic content (TPC), anthocyanin content (ANC), and antioxidant activity (DPPH, ABTS). The aerogels' morphology, crystallinity, surface area, porosity, and pore size were also determined. The statistical analyses were performed R Studio with ANOVA and Tukey's test at α = 0.05.

Results

The highest TPC (340 mg GAE/g dry PSP) and ANC (13 6mg C3G/100 g dry PSP) were achieved with SC-CO2 at 30 MPa, 35°C, and 20% cosolvent concentration operated for 180 min. For the aerogels, the 10% PSP with corn starch+anthocyanin extract aerogel showed the highest ANC (1403 mg/100 g) and TPC (2314 mg GAE/100g). The antioxidant activities were 40.1 mg TE/g with DPPH and 14.1 mg TE/g with ABTS in the aerogel. Finally, aerogels showed a three-dimensional open porous structure with a high surface area (~130 m2/g).

Significance

These findings highlight the suitability of SC-CO₂ drying as an eco-friendly, efficient method for developing anthocyanins-loaded aerogels. The results underscore the dual potential of PSP-based aerogels as natural colorants and functional ingredients for the food industry. Using spent PSP demonstrates a sustainable approach, aligning with the goals of reducing agricultural waste and using petroleum-based solvents.

Authors: Gabriel Laquete De Barros, Arda Tuhanioglu, Sumanjot Kaur, Leonardo Nora, César Valmor Rombaldi, Márcia Vizzotto, and Ali Ubeyitogullari