Research
 

 

Additional Research

Recent Research: New UK study compares antioxidants in frozen and fresh fruits and vegetables

Two independent studies, commissioned by the British Frozen Food Federation, show that frozen fruits and vegetables may have higher levels of antioxidants and phytochemicals than their fresh counterparts.

Researchers evaluated the nutrient content of commonly bought fresh and frozen fruit and vegetables from four UK supermarket chains. Researchers prepared and analyzed composite samples for amounts of antioxidants and plant compounds, including Vitamin C, polyphenols, anthocyanins, lutein and beta carotene, in the fresh produce, fresh-stored produce (after three days of storage in a refrigerator) and frozen produce.

Results show that frozen produce can be nutritionally comparable to fresh produce. The concentrations of antioxidants and phytochemicals measured in the frozen fruits and vegetables were similar to those of the corresponding fresh fruits and vegetables prior to refrigerated storage. And unlike frozen, the concentrations of some antioxidants and phytochemicals decreased during refrigerated storage to levels below those observed in the corresponding frozen produce.

To read reports of these studies, visit the British Frozen Food Federation.

Recent Research: 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.

Dr. Gayaneh Kyureghian
Lead Researcher

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).

Recent Research: Blueberry Research

Dr. Elliott Ryser

Dr. Elliott Ryser
Lead Researcher

New controlled application of chlorine dioxide in gas form is being studied as a means of reducing bacteria on fresh fruits and vegetables.

The first research project to be funded by a Foundation grant, titled Synergistic Impact of Chlorine Dioxide Gas and Various Freezing Rates on the Microbiological Quality of Frozen Blueberries, was the final phase of a five year study by Dr. Elliot Ryser and his team at Michigan State University. On May 14, 2008, a joint press conference between the Foundation and MSU was held at the Michigan Agricultural Experiment Station in Fennville, Michigan, to announce the project results. Among the attendees were blueberry growers who participated in the question and answer period. In August 2008, the project results, which showed significant reductions of bacteria, were presented at the International Association for Food Protection annual meeting. The study concluded that this treatment, followed by quick freezing, provides one means for ensuring high standards for blueberries, especially late season blueberries.

Future Research: Food Waste

The Frozen Food Foundation is elevating frozen's role in reducing food waste through an original research project.  

40 percent of all food produced in America is thrown away.  The average American family throws out an estimated 25 percent of the food and beverages they buy, adding up to anywhere from $1,250-$2,275 per year for a family of four.  All told,  both homes and businesses combine for nearly $162 billion worth of food waste each year in the U.S.

Through this new research initiative, the Foundation is seeking demonstrate the role of frozen food as a solution to combatting food waste, hunger and ensuring overall food security. 

Learn more about how your company can be part of the food waste solution by clicking here to donate to the initiative or by contacting Foundation Executive Director Adreinne Seiling at aseiling@frozenfoodfacts.org or (703) 821-0770.