As I have been studying food chemistry for four years, I have gotten used to people asking me what food chemistry is all about, as many people seem to confuse it with ecotrophology (a very popular Bachelor-degree course in Germany) or even nutritional science. When I enrolled in the MFS program, I had not considered that people might not be familiar with this scientific discipline. Although I knew for myself what food science means, I always had difficulties describing what it really is about. I guess that not only the definition from the background reading part but also the video "what is food science anyway" from http://www.ift.org/knowledge-center/learn-about-food-science/what-is-food-science.aspx (accessed Sept. 8th 2012) will help me to better explain the difference between food science and nutritional science. For this reason I will try to remember that "Food Science can be defined as the application of the principles of science, engineering and mathematics in order to study and acquire new knowledge on the physical, chemical and biochemical nature of foods. Food science is a broad field that is composed of specializations in food microbiology, food chemistry and food engineering. Food science also involves the study of sensory properties of food, and therefore, the psychology of food choice. From the information gathered by food science, the corresponding technologies can be applied to the utilization, processing, preservation and storage of food. This is known as food technology" (Background reading lesson 1).
The next topic which really caught my interest was in the "Apples and Apple Products" section of the background reading part. Although I have heard about special storage conditions in order to achieve longer shelf-life for certain fruits, I have never really given this topic much thought. The article from the Washington Apple Commission website (http://www.bestapples.com/facts/facts_controlled.aspx, accessed Sept. 8th 2012) was a very good introduction to Controlled Atmospheric Storage (CA). Reading the article made me want to learn more about CA, especially concerning vitamin stability but apparently there has not been done much research on this topic. Most of the scientific publications I found focused on the analysis or improvement of the degree of maturity and firmness of apples and other fruits after storage under controlled atmospheric conditions.
Another interesting topic is the trends in food consumption in Canada. The trend I wanted to learn more about is the increase in the organic food market. To do so, I read the article "Organic Foods" by Carl K., Winter and Sarah F. Davis, published in volume 71, Issue 9, pages R117 - R124 in the Journal of Food Science, November/December 2006. As my parents buy mainly organic food and grow many different vegetables in their garden, I am already familiar with some of the regulations for organic foods. However, I was surprised to read that the regulations in the US are similar to those in the European Union. The most interesting part about this article was the comparison of organic and conventional foods regarding quality and safety. As I had expected, the occurrence of pesticide residues on, as well as the levels of pesticide residues in organic foods are lower in comparison to conventional foods. In the course of the paper, the authors try to estimate the health risks caused by the consumption of pesticide residues in foods and come to the conclusion that "from a practical standpoint, the marginal benefits of reducing human exposure to pesticides in the diet through increased consumption of organic produce appear to be insignificant." Reading this really upset me, as the disadvantages of the usage of pesticides reach much further than the exposure of the consumer due to pesticide residues. Some of the additional disadvantages such as the severe health risks through occupational exposure or the environmental impact are mentioned very briefly. In my mind, this misrepresents the advantages and disadvantages of pesticide usage. As I remember from a toxicology class I have taken in the past semester, the main advantage of pesticide usage is to increase the yield in order to fight against starvation but the disadvantages are countless. Many pesticides show a certain acute toxicity, leading to many different health problems. Beyond that, many pesticides, especially organochlorine pesticides show a strong persistence and bioaccumulation, so that they can still be detected decades after their last usage.
Week 2: Sept. 10th -16th
Chemical and physical properties of food
The most part of the background reading on this topic seemed very familiar to me, when skimming through. For this reason I focused on the supplementary readings but I still enjoyed thinking about some of the questions in this part. My favorite question was the one asking why "instant puddings" did not need heat for swelling and gelatinization. I remember having thought about this matter years ago, when a friend talked me into buying an instant pudding. Unfortunately, I did not know much about food chemistry back then, especially not about the properties and characteristics of polysaccharides. And even now it took me quite a while to come up with a solution. Here is what I have come up with: The main difference between "real" pudding and "instant pudding" can be found in the binding agents which are mostly polysaccharides. While "real" pudding contains starch, which requires heat for swelling and, more importantly, gelatinization, "instant puddings" are made out of cold-water-soluble thickeners and binding agents with cold swelling properties. These could be for example carrageenan, carob bean gum or modified starches (cold water soluble, pregelatinized or instant starches.
The first paper I read was titled "Wheat ï¬‚our constituents: how they impact bread quality, and how to impact their functionality" by H. Goesaert and others. Although the first part of this paper (about the starch) initially seemed like repetition, it turned out to be interesting after all. For example, I did not know that both amylose and amylopectin had such an impact on the characteristics of bread. Yet, the second part about the proteins, in particular the information about the gluten proteins was more interesting. I now feel like an expert on gluten proteins and how their quality and quantity affect bread making. This article seemed to be good for background information to better understand the second paper I read "Recent advances in gluten-free baking and the current status of oats" by E. K. Hüttner and E. K. Arendt. As my former roommate suffered from celiac disease, I am already familiar with this topic. When reading this paper, I was surprised how little of the information given on the first few pages was new to me. Nevertheless it was nice to read and refresh my knowledge. Though the part where they introduced the recent development of gluten free bread using different processing techniques and ingredients was the most interesting. I was amazed while reading about the large number of approaches to solving the problem that the rheological characteristics of gluten free bakery products are very poor compared to gluten-containing products. I kept questioning myself why gluten free bread is often so poor quality, when there has been so much research about so many promising approaches. It seems like everyone (although a big proportion (about 1/7) of the references seem to be from the same author) only does a little basic research on a few components of which they expect an improvement in the quality of gluten free bread, but no one really seems to try and actually find the best composition for the different types of flowers. I guess that scientific studies in which all or at least a great number of the possible ingredients or technological processes are being combined and compared are too wide-ranging and too expensive to put into practice.
Another interesting point is, that this review cites quite a few papers on processing oat-bread, although it is said at the beginning that, according to the codex alimentarius, oats are not allowed in gluten-free products. This seems somewhat contradictory as this review is about gluten free baking and the status of oats. Well, the status of oats is being mentioned at the beginning as not allowed in gluten free products as the risk for contamination with gluten-containing cereals is very high. The authors do state, that gluten-free oats are being produced in a few countries, for example Finland, Sweden and Canada. But then they cite for example the paper "Oxidative and proteolytic enzyme preparations as promising improvers for oat bread formulations: Rheological, biochemical and microstructural background" by S. Renzetti, C.M. Courtin, J.A. Delcour and E.K. Arendt, which is about an experiment determining the effect of laccase and glucose oxidase on bread made out of supposedly gluten-free oat flour. Oddly enough, the oat flour used for this experiment is not marketed as gluten free at all (http://www.flahavans.com/product/porridgeoats/oats.htm). I looked that up, because in the abstract of this paper, the authors stated that they investigated the effect of laccase and glucose oxidase on bread made from gluten-free oat flour but in the materials and methods part it is not mentioned that the oat they used really was gluten free.
Week 3: Sept. 17th -23rd
Fat and Sugar Substitutes, -Sensory Perception of Foods
The first part of this week's lecture (about the sensory properties of food) was mostly repetition for me, as we had just talked about this topic in professor Scaman's Advances in Food Chemistry course. For this reason I started with the supplementary readings on fat replacers right away. Reading the publication "fat replacers" by Casimir C. Akoh, I was surprised about the vast number of different fat substitutes, of which I had never heard of before. The only substitutes that seemed familiar to me were olestra and SalatrimÂ®, as they were briefly mentioned during my undergraduate food chemistry course. All the other fat substitutes such as sucrose fatty acid esters (SFE), structured lipids (SL), dialkyl dihexadecylmalonate (DDM) and esterified propoxylated glycerols (EPGs), as well as the protein-based fat mimetics like SimplesseÂ® and the carbohydrate-based fat mimetics like for example gums, starches, pectin or cellulose were new to me.
I read the "Information Statement on Olestra" from the Institute of Food Science & Technology for a funny reason, actually. I remember my former food chemistry professor saying, that olestra was not allowed in the European Union, because of the side effects from high-quantity intake of olestra. She said that one could expect adults to read the label carefully and thus to know about the possible risks and also to stop eating after consumption of the suggested maximum amount. But this cannot be expected from children. My professor then joked, that if olestra were to be allowed in food products in Germany, there would have to be an age restriction on these products, as is on alcohol for example. As we did not go into this in any detail, I wanted to use the supplementary readings to find out more about olestra, in particular about the side effects and also about the amount of olestra that causes these effects. Although the IFST's "Information Statement on Olestra" gave a good summary of the effects on gastrointestinal system and olestra-related anal leakage as well as on the effect on fat-soluble vitamins, it turned out that this article did not answer all my questions. I still wanted to have some information on some kind of an acceptable daily intake (ADI) for olestra. After a long internet research I finally found a website with information on this matter (http://www.cspinet.org/olestra/11cons.html). I was very surprised to read that there is no such thing as an ADI for olestra. Although I am not too sure about the credibility of this website which does not seem to simply state scientific facts but gives a unilateral opinion on olestra (stressing its disadvantages), the section on the ADI seems pretty logic to me. Plus this would also explain why it was so hard to find any information on this matter. On further research, I found this presentation from Alan M. Rulis about "Food Safety and "Nutritional Risk": "Bioactive" Food Components" on the CSL / JIFSAN Symposium on Food Safety and Nutrition (http://jifsan.umd.edu/docs/csl-jifsan-2005/csl2005_Rulis.pdf), which gives the exact opposite view on olestra (justifying its GRAS-status) than the website above. In the summary, Alan M. Rulis states that there are no adverse effects upon which one could "determine an ADI in the traditional sense". Rulis justifies this statement by saying that the vitamin loss can be compensated by vitamin supplementation and that the gastrointestinal effects of olestra do not affect the consumer's health adversely. The one-sided presentation of olestra by Rulis is probably due to his work for the U.S. Food and Drug Administration (http://www.exponent.com/alan_rulis/).