Broccoli, carrots, and green beans (grown in 2 consecutive years) were randomly divided into 3 treatments: fresh-refrigerated (F-R), frozen (FZ) or canned (C) (carrots only). FZ or C vegetables were processed within 24 h and stored for up to 1 yr. F-R vegetables were held at 4 °C for 3 wk (broccoli and green beans) or 6 mo (carrots). Trans b-carotene (Tb-C) and total ascorbic acid (AA) were determined at specified times, before and after microwave cooking. Vitamin content differed between years due to environmental conditions. Blanching resulted in AA loss, but retention remained stable after freezing broccoli and green beans. F-R green beans lost >90% AA after 16 d storage. Linear decreases in AA were found in most F-R or FZ vegetables. Tb-C decreased slightly during freezer storage. Reductions in Tb-C occurred in canned carrots. Microwave cooking had minimal effects on AA or Tb-C.
Reduced ascorbic acid (RAA) and Vitamin A (carotenoid) contents of six vegetables obtained from six cities in the United States at two seasons of the year were determined. Mean RAA content (mg/lOOg) of cabbage was 45.2, carrots 7.8, celery 6.0, corn 6.5, onions 8.4, and tomatoes 15.3. Vitamin C in cooked cabbage was 22.1, corn 6.2, and onions 5.7 mg/100g. Mean vitamin A activity (I.U.) of carrots was 15,228, cabbage 114, celery 133, corn 219, and tomatoes 750. In cooked cabbage and corn, vitamin A content was 89 and 217 I.U., respectively. The RAA and vitamin A content of vegetables from the six geographical areas varied significantly. Vitamin concentrations were generally lower than tabulated values. Retention of RAA in cooked cabbage was 52%; in onions, 58%; and in corn, 98%. Vitamin A retention in cooked cabbage was 82%, and in cooked corn was 98%.
Reduced ascorbic acid (RAA) content, total chlorophyll and green color retention, enzyme activities and texture changes were followed in broccoli spears packaged in polymeric film and nonpackaged during 96 hr storage (10°C). Concentrations within packages monitored by gas chromatography were (CO,) 8% and (02) 10%. RAA retention, moisture content, total chlorophyll and color retention were greater in packaged broccoli. No differences were found between packaged and nonpackaged broccoli for ascorbate oxidase and peroxidase activities, or texture.
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