Storage of fresh-cut swede and turnip in modified atmosphere: effects on vitamin C, sugars, glucosinolates and sensory attributes

Abstract

Fresh-cut swede (Brassica napus L. var. napobrassica (L.) Rchb.) and turnip (Brassica rapa L. ssp. rapifera Metzg.) in modified atmosphere packaging (MAP) were stored for 5 or 10 d, at 5°C or 10°C. Two passive and one active (flushed with 5% O2 at sealing) modified atmospheres were tested. Vitamin C content was not influenced by the experimental parameters. The content of total sugar decreased during storage for both vegetables, and significant effects of time, temperature and atmosphere were observed for glucose, fructose and sucrose. Total aliphatic and indolic glucosinolates increased in swede during storage, while for turnip total aliphatic glucosinolates decreased and total indolic glucosinolates increased. Atmosphere composition affected glucosinolates, and the response varied between individual glucosinolates. Taste and flavour were more influenced by time and temperature, than by atmosphere in both vegetables. However, modified atmosphere with low O2 concentration reduced discolouration related changes, especially for turnip. Positive correlation was observed between sugar content and sweet taste for both vegetables. Sweet and bitter tastes were negatively correlated for swede. Low temperature and short storage time were the most important criteria to prevent changes of appearance, odours, taste and flavours, and contents of sugar and glucosinolates of fresh-cut swede and turnip.