The Gentle Touch

Technical talk with Dr. John Michaelides of the Guelph Food Technology Centre.

This column is written by Dr. John Michaelides of the Guelph Food Technology Centre.

Question: Why do we need gentle processing technologies for the production of functional ingredients and functional foods and how does this affect the baking industry?

Answer: Today’s consumers are well aware of the relationship between diet and health. Greater awareness is leading to consumer questioning and investigation of food quality, food safety and nutritional claims. One concern gaining consumer and media attention is the impact of some food processing technologies on nutritional content. While providing an essential function in terms of food safety and efficiency, some processing technologies may eliminate or damage essential nutrients, in turn depleting some of the health benefits certain foods provide.

Fruits, vegetables, cereals, milk and other foods contain essential vitamins and minerals. These components, considered vital to human health, are often reduced or eliminated during the various processing methods for foods such as cooking, drying, freezing or dry or wet milling, etc. Many deficiencies are addressed through the re-introduction of vitamins and minerals based on voluntary or mandatory fortification programs. But all the same, consumers are questioning if vitamins and minerals are removed from flour in the milling process? Do the blueberries in blueberry muffins maintain their antioxidant properties after baking, do the functional benefits of gogi berries survive the pasteurization process in a fruit punch or does Salba® baked into a cracker still deliver all the nutrients available in the raw form?

Gentle processing technologies can range from extraction and separation to drying, cooking, preservation and filtration. In the area of functional ingredient manufacturing, extraction and separation are critical in preserving the healthy components. For example, micro-filtration has been successfully employed when pasteurizing skim milk. This technology involves the filtration of skim milk through membranes that can remove most of the bacteria present and reduce the temperature regime required for pasteurization.
Extraction of functional ingredients such as antioxidants, Isoflavones and oil from fruits, vegetables and other plant materials can be successfully carried out by the use of supercritical fluid extraction processes using liquid carbon dioxide under pressure. This method is considered a safe and environmentally friendly alternative to the use of solvents such as hexane.

Often functional ingredients need to be dried to the level of moisture that will prevent spoilage and ensure food safety. The various components that provide the health benefits may be sensitive to high temperatures that conventional drying techniques provide. Several new and improved drying technologies were recently presented at a breakfast seminar organized by the Guelph Food Technology Centre. The breakfast explored two new technologies in drying; MCD Refractance Window technology, which is used for the drying of fruit and vegetable purees and Nutriloc technology, which is used for drying fruit and vegetable pieces. Both of theses drying technologies can be effective at low temperatures. In addition, advancements in freeze drying were presented. Freeze drying is traditionally a time-consuming process, but with new advancements and the introduction of minimal heat the process can be sped up, making freeze drying a more viable option. The aim of these three drying technologies is to introduce gentle drying in order to preserve the health benefits of the ingredients produced.

The next step for manufacturers is ensuring that functional ingredients maintain the positive health benefits from production to consumer consumption. Manufacturing processes are often harsh in order to ensure food safety. Therefore the functional attributes of the products may be compromised. It is essential when we develop functional food products to take all processing parameters into consideration.

Specifically, how those processes will affect the functional ingredients. In some cases the production processes are not compatible with the functional ingredient being added. An example of incompatibility is the incorporation of probiotic bacteria in bread. During the baking process bread reaches temperatures of more than 95 C, which will kill these helpful bacteria.

Other preservation technologies used to extend shelf life, which do not require heat and are effective in reducing or eliminating spoilage and the growth of pathogenic micro-organism, are currently used in the industry but are limited to certain applications.

High pressure, pulse electric field technologies and irradiation require no heat but are not widely used due to certain application limitations. More recently, the application of radio frequency is being tested at the pre-commercialization stage and it is expected to be available on the market in 12 to 18 months. The developers claim that the technology will destroy harmful bacteria and at the same time eliminate surface overheating and reduce the thermal loads while maintaining quality, nutritional and healthy attributes.
The baking industry is in an ideal position to introduce functional food products that will succeed in today’s competitive market. We have already seen the introduction of breads with additional calcium, soy and isoflavones or omega oils both from fish and flax seed.  As more sophisticated functional ingredients are being introduced into baked goods we need to make sure the ingredients we use contain the functional components the suppliers claim and our production processes preserve the efficacy of the functional ingredient throughout the lifecycle of the product.
 
Funding for this report was provided in part by Agriculture and Agri-Food Canada through the Agricultural Adaptation Council’s CanAdvance Program.

For more information, or fee for service help with product or process development needs please contact the GFTC at 519-821-1246, by fax at 519-836-1281, by e-mail at gftc@gftc.ca.