Seasonal variability of the vitamin C content of fresh fruits and vegetables in a local retail market.

BACKGROUND

Seasonal variation of vitamin C in fresh fruits and vegetables is not reflected in food composition database average values, yet many factors influence content and retention.

RESULTS

Fresh fruits and vegetables were sampled on three occasions in each season, from the same local retail outlets, for 1 or 2 years. Vitamin C was significantly higher in winter-sampled spinach (436 mg kg ) compared with spring (298 mg kg ) and summer/fall (180 mg kg ); in potatoes in summer/fall (156 mg kg ) versus winter/spring (106 mg kg ); and in oranges in winter (616 mg kg ), spring (592 mg kg ), and summer (506 mg kg ). Ranges were dramatic among sampling occasions for broccoli, oranges, potatoes, and spinach (700-1210 mg kg , 420-780 mg kg , 70-280 mg kg , and 90-660 mg kg respectively). Mean values for apples, bananas, tomatoes, and potatoes differed from the USDA National Nutrient Database for Standard Reference (SR) average by ≥10% of the daily recommended intake (90 mg). For broccoli, oranges, and spinach, vitamin C was substantially above or below the SR range in 50-100% of the samples. For spinach, the average content did not differ from SR, but vitamin C in winter was 55% higher than SR.

CONCLUSION

Database average values for vitamin C in fresh produce can significantly over- or underestimate the content in a specific food supply. © 2018 Society of Chemical Industry.