Nutrition Research Project

Eating more fruits and vegetables matters when it comes to maintaining a healthy weight and potentially reducing the risk of certain diseases. Fruits and vegetables of all kinds supply valuable nutrients such as fiber and potassium, as well as a variety of vitamins. In addition, people who eat more generous amounts of fruits and vegetables as part of a healthy diet are likely to have reduced risk of chronic diseases, including stroke, type 2 diabetes, certain types of cancer, and perhaps heart disease and high blood pressure.

Despite all the reasons we should eat more of them, research indicates that most individuals are not meeting the current recommendations for intake of fruits and vegetables. Commonly cited barriers to consumption include lack of time, cost, differing preferences among family members and variations in product quality.

The availability of frozen fruits and vegetables provides convenience, consistent quality and variety while contributing to overall nutrient intake. However, misconceptions about the quality and nutritional value of frozen fruits and vegetables discourage some consumers from incorporating them into their daily menu. A recent survey of mothers conducted by the Produce for Better Health Foundation (2010) found that only 41 percent of Generation X moms purchase frozen fruit because they believe it to be nutritious; only 50 percent indicated they purchase frozen vegetables for the same reason. Comparatively, 85 percent of Generation X moms purchase fresh fruit because they believe it to be nutritious; 84 percent indicated they purchase fresh vegetables for the same reason.

Research suggests that fruits and vegetables begin to lose valuable nutrients – particularly vitamins – immediately after harvesting. Movement of produce through the supply chain from field to grocery can take several days and perhaps longer for some specialty items. Thus, once the consumer has purchased fresh produce at the grocery, wholesale, convenience or club store, a substantial loss of some nutrients may have occurred. Furthermore, several more days may lapse between the time the produce is purchased and the time it is actually consumed, potentially leading to additional nutrient loss.

In contrast, produce intended for commercial freezing is processed within hours of harvesting. Although a loss of some nutrients may occur as a result of processing, research indicates these losses may be minimal. In fact, after freezing, fruits and vegetables generally remain good or excellent sources of the particular nutrients they contain before harvesting.

Research Goal And Objectives

The goal of this research is to demonstrate the nutritional benefits of frozen fruits and vegetables relative to fresh produce obtained at the point of purchase. Specifically, the objective is to compare the nutrient content of fresh versus frozen fruits and vegetables under conditions that duplicate: a) what is available to the consumer and b) how consumers behave relative to purchase and storage.

The sampling process reflects the actual behavior of consumers. That is, the methodology reflects where consumers might purchase both fresh and frozen fruits and vegetables (i.e. supermarket chain, warehouse store, small food store) and what may be considered typical post-purchase storage and handling practices by consumers. Nutrient analyses will be conducted once immediately after purchase, and again approximately four days after purchase, reflecting typical storage behavior.

Phase I – Literature Review

A review of existing food processing nutrition and dietary literature speaking to the nutritional value of frozen and non-frozen fruits and vegetables completed by The Food Processing Center at the University of Nebraska – Lincoln. The Phase I results also identify gaps in the literature that will guide the quantitative analysis to be completed in Phase II.

Download Phase I Literature Review
Download References

Phase II – Quantitative Analysis

Researchers at the University of Georgia’s Department of Food Science & Technology will demonstrate the nutritional benefits of frozen fruits and vegetables relative to their fresh counterparts obtained at the point of purchase through the reporting of key nutrients.

Fruits and vegetables to be sampled include:

  • Strawberries
  • Blueberries
  • Spinach
  • Green beans
  • Broccoli
  • Cauliflower
  • Peas
  • Corn

Nutrients to be analyzed include:

  • Vitamin C
  • Total β-carotene, reported as vitamin A
  • Total folate
  • Aluminum
  • Calcium
  • Chromium
  • Copper
  • Iron
  • Magnesium
  • Manganese
  • Potassium
  • Sodium
  • Zinc

For the results to be meaningful, critical attention will be paid to the following:

  • Adopting a statistically-valid sample plan
  • Handling techniques of the purchased samples
  • Timing of sample analysis or nutrient stabilization
  • Ensuring a representative number of samples for analysis from each batch

All data will be reported as means ± standard deviation on fresh and dry weight bases with different means for the three “treatment” types (frozen, fresh and fresh after storage).