Oxidative stability of baked products incorporated with Phyllanthus emblica seed extract: a functional alternative to synthetic antioxidants

Abstract

Lipid oxidation limits shelf-life of bakery products, typically controlled by synthetic antioxidants (BHT, BHA, and TBHQ) with safety concerns. This study aimed to evaluate ethyl acetate extract of Phyllanthus emblica seed (PSE) as a natural antioxidant to extend the shelf-life of sponge cakes and biscuits. The extract was assessed for antioxidant activity, thermal stability, antimicrobial activity, and toxicity prior to application. HPLC analysis identified seven major phenolic compounds: gallic, vanillic, sinapic, p-coumaric, and ellagic acids, myricetin, and quercetin. PSE showed significantly (p < 0.05) higher antioxidant activity than synthetic antioxidants, with lower IC₅₀ in DPPH (41.23 µg mL⁻¹) and ABTS˙⁺ (29.31 µg mL⁻¹) and higher FRAP (180.34 µg mL⁻¹). PSE retained over 90% antioxidant activity at 180 °C for 2 h, exceeding BHT (62%), BHA (63%), and TBHQ (87%). Toxicity assessment indicated low toxicity, with an IC₅₀ of 1025.37 µg mL⁻¹ (Caco-2 cells) and an LC₅₀ of 1832.71 µg mL⁻¹ (zebrafish embryos), and no effects on survival, hatching, or heartbeat were observed at 200 µg mL⁻¹, the bakery application concentration. Sponge cakes and biscuits were treated with PSE (200 µg mL⁻¹) and compared with BHT, BHA, TBHQ, and control (no antioxidant). Sponge cakes with PSE retained peroxide value (PV) and TBARS below thresholds (0.5 meq per kg and 0.3 mg kg⁻¹) for 14 days, while controls exceeded limits within 7 days. In biscuits, PV remained below 1.0 meq per kg for 56 days with PSE, BHT, and TBHQ. PSE extended microbial shelf-life to 12 days in cakes and 84 days in biscuits without affecting sensory quality. Findings highlight PSE as a thermally stable, non-toxic, and effective natural alternative to synthetic antioxidants in bakery products.