Different Effects of Vitamin C-Based Supplements on the Advance of Linseed Oil Component Oxidation and Lipolysis during In Vitro Gastrointestinal Digestion

Although widely consumed, dietary supplements based on Vitamin C contain high doses of this compound, whose impact on lipid oxidation during digestion needs to be addressed. Therefore, the effect of seven commercial supplements and of pure l-ascorbic acid and ascorbyl palmitate on linseed oil during in vitro gastrointestinal digestion was tackled. The advance of lipid oxidation was studied through the generation of oxidation compounds, the degradation of polyunsaturated fatty acyl chains and of gamma-tocopherol, by employing Proton Nuclear Magnetic Resonance. Supplements containing exclusively l-ascorbic acid enhanced the advance of linseed oil oxidation during digestion. This was evidenced by increased formation of linolenic-derived conjugated hydroxy-dienes and alkanals and by the generation of conjugated keto-dienes and reactive alpha,beta-unsaturated aldehydes, such as 4,5-epoxy-2-alkenals; moreover, gamma-tocopherol was completely degraded. Conversely, supplements composed of mixtures of ascorbic acid/salt with citric acid and carotenes, and of ascorbyl palmitate, protected linseed oil against oxidation and reduced gamma-tocopherol degradation. The study through Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry of the volatile compounds of the digests corroborated these findings. Furthermore, a decreased lipid bioaccessibility was noticed in the presence of the highest dose of l-ascorbic acid. Both the chemical form of Vitamin C and the presence of other ingredients in dietary supplements have shown to be of great relevance regarding oxidation and hydrolysis reactions occurring during lipid digestion.

Variasi Antioksidan dalam Pembuatan Protected Active Dried Yeast

Abstrak. Penggunaan antioksidan pada pembuatan protected active dried yeast (PADY) dapat memperpanjang umur simpan ragi kering. Antioksidan yang sering digunakan adalah antioksidan sintesis BHA dan BHT yang diduga bersifat karsinogenik. Penelitian ini bertujuan untuk mencari alternatif antioksidan yang lebih aman. Lima antioksidan yaitu asam sitrat, asam askorbat, tokoferol, natrium eritrobat, dan askorbil palmitat pada rentang konsentrasi 0,025-0,5% diuji pada suspensi ragiuntuk mempelajari efek inhibisi dari antioksidan tersebut. Uji laju produksi CO2 menunjukkan sifat noninhibisi dari asam askorbat, natrium eritorbat, asam sitrat, dan tokoferol, sedangkan sifat inhibisi askorbil palmitat dan BHT perlu diteliti lebih lanjut. Formulasi antioksidan terpilih untuk produksi PADY adalah asam sitrat 0,5%, asam askorbat 0,5%, dan tokoferol 0,5%. Pengeringan ragi dengan spray dryer menghasilkan PADY dengan kadar air sesuai standar. PADY dengan sifat fisik terbaik adalah variasi asam sitrat 0,5% dan asam askorbat 0,5% karena kelarutan dalam air yang baik serta granula yang lebih halus. Stabilitas vitalitas PADY diukur selama 45-50 hari, dan didapatkan PADY dengan antioksidan asam askorbat 0,5% memiliki konstanta laju kematian terendah, yaitu 0,0492/hari, setara dengan umur simpan 20 hari. Dengan demikian, formulasi antioksidan asam askorbat 0,5% berpotensi untuk dikembangkan pada produksi PADY. Kata kunci: antioksidan, ragi kering, stabilitas, vitalitas. Abstract. Variation of Antioxidant in Production of Protected Active Dried Yeast. The use of antioxidants in production of protected active dried yeast (PADY) can increase dried yeast’s shelf life. Usually, the antioxidants used are synthetic antioxidants such as BHA and BHT, which are known to be carcinogenic. Therefore, the aim of this research is to study antioxidant alternative that is safer. Five antioxidants, i.e. citric acid, ascorbic acid, tocopherol, sodium erythorbate, and ascorbyl palmitate in concentration range of 0.025-0.5% were tested on yeast suspension to study its inhibitory effect. CO2 production rate test showed noninhibitory characteristic of ascorbic acid, sodium erythorbate, citric acid, and tocopherol, whereas ascorbyl palmitate and BHT showed inhibitory characteristic. Formulations of antioxidants selected are 0.5% citric acid, 0.5% ascorbic acid, and 0.5% tocopherol. Spray drying of yeast resulted in PADY with moisture content within standard. PADYs with the best physical properties are 0.5% citric acid and 0.5% ascorbic acid variation due to good water solubility and finer granules. Vitality stability of PADY was measured for 45-50 days. PADY with 0.5% ascorbic acid had the lowest death rate constant, i.e. 0.0492/day, which is equivalent to 20-days shelf life. Thus, ascorbic acid antioxidant formulation of 0.5% can be developed in the production of PADY. Keywords: antioxidant, dried yeast, stability, vitality.