Vitamins profile as an indicator of the quality of frozen Agaricus bisporus mushrooms

• In mushrooms niacin was the most abundant vitamin, followed by riboflavin.
• Pre-treatment and period of storage had the greatest effect on vitamins profile.
• The greatest changes occurred between months 6 and 12 of storage.
• The greatest losses were found in vitamin B1, l-ascorbic acid and α-tocopherol.
• Freezing method affected only vitamin B3, higher levels were found in cryogenically frozen products.

Fresh mushrooms have been known as a functional food, especially as a good source of vitamins from B-group. The work determined the effect of pre-treatment (blanching, vacuum soaking), method of freezing (air-blast and cryogenic), temperature (−20 °C, −30 °C) and period (0, 6, 12 months) of frozen storage on the vitamins profile in white A. bisporus. Niacin and riboflavin were the most abundant vitamins in all mushroom products (154–362 mg; 1.57–5.06 mg/100 g dm, respectively). The greatest influence on the vitamins profile was pre-treatment. The highest levels of vitamin B3 and L-ascorbic acid were found in blanched mushrooms, vitamin B6 in vacuum soaked, α-tocopherol and vitamin B1 in unblanched. The greatest losses occurred between the 6th and 12th month of storage, and therefore mushrooms should not be stored for longer than 6 months. After storage the greatest losses were found in vitamin B1, L-ascorbic acid and α-tocopherol. A. bisporus mushrooms contain small amounts of L-ascorbic acid and α-tocopherol, therefore the level of vitamin B1 may be regarded as a quality indicator. The freezing method affected only vitamin B3, with levels higher after cryogenic than air-blast freezing. The storage temperature generally had no effect on vitamin levels.