Introduction to Food Biochemistry

by Olamide Adeleye

Biochemistry attempts to emphasise the importance of Biochemistry in a field of food science and to provide a deeper understanding of those chemical change occurring in food. Food Biochemistry is concerned with the breakdown of food in the cell as a source of energy. Many biochemical reactions and their products are the basis of much of food science and technology. Food scientists must be interdisciplinary in their approaches to studying and solving problems that require the integration of several disciplines, such as physics, chemistry, biology and various social sciences (e.g. sensory science, marketing, consumer attitude/acceptability).

For example, in the development of food packaging materials, one must consider microbiological, environmental, biochemical (flavour/nutrient) and economic questions, in addition to material/polymer science.  In today’s market, product development considerations may include several of the following: nutritional, environmental, microbiological (safety and probiotic), nutraceutical and religious/cultural questions, in addition to cost/marketing and formulation methods. An ideal food product would promote healthy gut microflora, contain 20g of vegetable protein with no limiting amino acids, and have 25% of the daily fibre requirement. It would also be lactose-free, nut-free, fat-free, antibiotic-and pesticide-free, artificial colour-free, sugar-free and contain certified levels of phytosterols.

The product would contain tasteless, odourless, mercury-free, cold-pressed, bioactive omega 3-rich fish oil harvested using animal-friendly methods. Furthermore, it would be blood sugar-stabilising and heart disease-preventing, boost energy levels, not interfere with sleep, be packaged in minimal, compostable packaging, manufactured using ‘green’ energy, transported by biodiesel-burning trucks and be available to the masses at a reasonable price. At their most fundamental levels, growing crops and raising food animals, storing or ageing foods, processing via fermentation, developing food products, preparing and/or cooking, and finally ingesting food are all ways of bringing about or even preventing biochemical changes. Furthermore, methods to combat both pathogenic and spoilage organisms are based upon biochemical effects, which include acidifying their environments, heat-denaturing their membrane proteins, oxygen depriving, water-depriving and/or biotin-synthesis inhibiting of the microbes. Only recently have the basic mechanisms behind food losses and food poisoning begun to be unravelled.

Food scientists recognised long ago the importance of a biochemistry background, demonstrated by the recommendation of a general biochemistry course requirement at the undergraduate level by the Institute of Food Technologists (IFT) in the United States more than 40 years ago. Many universities in various countries now offer a graduate course in food biochemistry as an elective or have food biochemistry as a specialised area of expertise in their undergraduate and graduate programs. The complexity of this area is very challenging; a content-specific journal, the Journal of Food Biochemistry, has been available since 1977 for scholars to report their food biochemistry-related research results.

Our greater understanding of food biochemistry has followed developments in food processing technology and biotechnology, resulting in improved nutrition and food safety. For example, milk-intolerant consumers can ingest nutritious dairy products that are either lactose-free or by taking pills that contain an enzyme to reduce or eliminate lactose. People can decrease gas production resulting from eating healthy legumes by taking α-galactosidase (produced by Aspergillus niger) supplements with meals. Shark meat is made more palatable by controlling the action of urease on urea. Tomato juice production is improved by proper control of its peptic enzymes. Better colour in potato chips results from removal of sugars from the cut potato slices. More tender beef results from proper aging of carcasses or at the consumer level, the addition of instant marinades containing protease(s). Ripening inhibition of bananas during transport is achieved by controlling levels of the ripening hormone – ethylene – in packaging. Proper chilling of caught tuna minimises histamine production by inhibiting the activities of certain bacteria, thereby avoiding scombroid or histamine poisoning.

Beyond modified atmosphere packaging, ‘intelligent’ packaging materials that respond to and delay certain deteriorative biochemical reactions are being developed and utilised. The above are just a few of the examples that will be discussed in more detail in subsequent reports.

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