Changes in the content of low molecular weight carbohydrates in frozen immature bean seeds depending on type and method of processing prior to freezing

• Common bean seeds at the wax stage of maturity were investigated.
• Seeds raw and two frozen products prepared for consumption were investigated.
• Seeds were blanched or cooked before freezing.
• Preparation methods before freezing had no effect on analysed compounds content.
• Frozen storage time had no effect on analysed compounds content.

Immature seeds of five bean cultivars (flageolet-type and those intended for dry-seed production) were evaluated for changes in the content of water soluble carbohydrates due to freezing, storage and preparation for consumption. Analyses were conducted in two differently treated products: 1. blanched, frozen, stored for 0–12 months, then boiled, 2. boiled, frozen, stored for 0–12 months, then microwave heated. Fresh bean seeds contained 2449.3–3182.6 mg total soluble sugars per 100 g of edible portion, of which raffinose family oligosaccharides (RFOs) comprised 43.8–49.3%. The dominant raffinose family oligosaccharide was stachyose. In seeds having undergone either of the above processing methods and then prepared for consumption, the content of total soluble sugars decreased by 51–64% and RFOs by 40–54%, depending on the cultivar. In general, there were no differences in the content of soluble sugars in products prepared for consumption in different way both immediately after freezing and after 12-month storage.