The potential of zein nanoparticles to protect entrapped β-carotene in the presence of milk under simulated gastrointestinal (GI) conditions

•Stability of β-carotene during GI transit was improved by nanoentrapment.•Nano-entrapped β-carotene in zein NPs was protected until release.•Nano-enabled improvement in stability and antioxidant activity was less in milk.•Zein nanoparticles proved superior to nanoemulsions for nanodelivery of β-carotene.

The addition of nanoentrapped β-carotene in milk is proposed as a valid method to improve stability and enhance antioxidant activity of β-carotene during GI transit. This study focused on two types of delivery systems, nanoparticles and nanoemulsions, and compared their ability to enhance the physicochemical stability and antioxidant activity of β-carotene in the presence of milk under simulated GI conditions. β-Carotene-loaded zein nanoparticles and nanoemulsion, stabilized by pluronic F127 and lecithin, were synthesized and added to liquid milk. Degradation of β-carotene was spectrophotometrically analyzed, and antioxidant activity was measured using ABTS and TBARS assays in simulated gastric fluid (SGF) with pepsin for 2 h and in simulated intestinal fluid (SIF) with pancreatin for 24 h. The initial amount of β-carotene remained at 18.30 ± 1.29% and 4.41 ± 2.51% after a 26 h total time of GI exposure in nanoentrapped and emulsified forms, respectively. In both systems, nanoentrapment proved to be beneficial to beta-carotene stability, but this benefit was decreased in the presence of milk. The improvement in antioxidant activity of nanodelivered β-carotene was confirmed by ABTS and TBARS assays. In conclusion, zein nanoparticles improved chemical stability and antioxidant activity of entrapped beta-carotene versus emulsions in the presence of milk under simulated gastrointestinal environments.

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