The aim of the study was to examine and compare oxidative stability of refined (peanut, corn, rice bran, grapeseed, and rapeseed) oils. The oils were subject a Schaal Oven Test (temperature 63 ± 1 °C) and a Rancimat test (temperature 120 °C) and their stability was compared at the 1st and 12th month of storage. Changes in the peroxide (PV) and anisidine (AnV) values in the thermostat test were the fastest in rapeseed oil and grapeseed oil. The best quality was preserved by peanut and corn oils both in the first and the twelfth month of storage. The induction times for the rice bran, corn, peanut, and rapeseed oils were similar from 4.77 h to 5.02 h in the first month and from 3.22 h to 3.77 h in the twelfth month. The shortest induction times were determined for grapeseed oil: 2.4 h and 1.6 h, respectively. A decrease of oxidative stability of about 30% was found in all the oils after 12 months of storage. The PV of 10, determined in the thermostat and Rancimat tests, were achieved at the latest in corn oil and the fastest in rice bran oil.

Effects of agglomeration of beta-carotene microencapsulated by spray drying on its stability were analysed. Mixtures of Arabic gum (GA), maltodextrin (MD), modified starch (OSA), and whey protein (WP) were used as carriers. GA + MD and OSA + MD microcapsules were subjected to agglomeration. All the samples were stored for 60 days with access to daylight. Stability of the emulsions had a significant effect on efficiency of microencapsulation but had no effect on beta-carotene retention during sample storage. Among the tested samples, the highest retention of colorant characterized the samples containing GA + MD. The agglomeration process reduced the content of beta-carotene in the microcapsules almost by half. However, retention of the colorant during storage of the microcapsules was increased most of all and half-life of beta-carotene was significantly prolonged. Changes in L* and a* colour parameters during storage were more limited in the case of agglomerated samples.