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Papers in this issue disclose how much we don't know about the foods we eat. Each paper takes us closer to more knowledge. For the most part, they aren't particularly difficult to read, and can provide the difference between a rapid solution to a problem, and a slow one.

Microwave cooking or reheating of foods has been on the list of important issues for a number of years, and remains so. The study done on “Microwave Heating of Cooked Pork Patties as a Function of Fat Content,” reported by researchers from two Spanish universities may have been done to solve local problems, but should be extremely interesting to those in the U.S. who provide the gazillion breakfast sandwiches sold daily from U.S. fast-food restaurants. The interrelationship between microwave heating and fat could make it possible to heat the sandwich faster, or risk overheating, thus burning the diner's mouth. The researchers found that higher levels of fat made a patty heat faster, and that it made a difference between two-power levels of the microwave ovens. The researchers concluded: “Heat transfer does not appear to be the key factor that drives the temperature to rise. The temperature increase should be attributed to other factors, probably related to the interaction of fat with the electromagnetic field, and it may be conditioned by viscosity changes due to phase transitions. This appears to favor use of specific amounts of fat in a sausage patty to manage heating times. We assume more work will be done to refine this.”p E57-63.

Where does the Flavor Go?

  1. Top of page
  2. Where does the Flavor Go?
  3. Moving Beyond the Database
  4. How does the Consumer's Garden Grow?
  5. The Ins and Outs of Sour
  6. Maximizing the Quality of Salmon during Processing

A silly song from the 50's asked whether the spearmint stayed on the bedpost over night, and every since, (and before, although most of us were glad to have anything that tasted good, after rationing) everyone has been interested in keeping the flavor where it belongs, and having it go into the mouth. According to the paper “Characterization of Hydrophobic Flavor Release Profile in Oil-in-Water Emulsion,”“flavor release from food depends on the composition and the microstructure of the matrix, the properties of aroma compounds (molecular weight, solubility, hydrophobicity, and so on), and their interactions with other food components. Proteins, lipids, and polysaccharides have been shown to affect the rate of flavor release because of their ability to bind, solubilize, or retard the mass transfer of flavors. “This paper reports research by scientists from Agri-Foods Canada, who developed an instrumental approach to the difficulties of determining the role that emulsion composition has on aroma release intensity and persistence. The important role of emulsion oil content on flavor release profile has been shown using their adaptation of a GC mechanism. The researchers conclude that the rate of flavor release is strongly associated with oil concentration. Again, the oil phase acts as an aroma reservoir and flavor release is slowed down as the oil fraction of the emulsion increases. p S125-129.

Moving Beyond the Database

  1. Top of page
  2. Where does the Flavor Go?
  3. Moving Beyond the Database
  4. How does the Consumer's Garden Grow?
  5. The Ins and Outs of Sour
  6. Maximizing the Quality of Salmon during Processing

Food composition databases provide food formulators with the information needed to provide a nutrition label, but fail to inform the consumer how much good the food will do him or her. This is especially true of phytochemicals. The authors of a paper titled “Food Microstructure Affects the Bioavailability of Several Nutrients” are from Pontificia Univ. Católica de Chile. Being from an area that grows large amounts of fruits and vegetables, both for local use and for export, they are particularly interested in the specific usefulness of the phytochemicals found in their crops. They note the difference between bioavailability and bioaccessibility, and carefully define the role between microstructure of foods and the utility of the phytochemicals therein. They note five important definitions and their uses:

Bioavailability: The fraction of ingested nutrient that is available for utilization in normal physiologic functions and for storage.

Bioconversion: Fraction of bioavailable nutrient that is converted into the active form.

Bioefficacy: Fraction of ingested nutrient that has a nutritional effect.

Bioaccessibility: Fraction that is released from food matrix and is available for intestinal absorption (typically based on in vitro procedures).

Bioequivalence: Absence of a significant difference in the rate and extent to which 2 active ingredients become available at the site of action, when administrated at the same molar dose under similar conditions.

They also discuss some specific nutrients and their early references. The article concludes that there are still an awful lot of unknowns and that the pursuit of answers requires much careful work. But it also provides a good roadmap for those seeking that knowledge. p R21-32.

How does the Consumer's Garden Grow?

  1. Top of page
  2. Where does the Flavor Go?
  3. Moving Beyond the Database
  4. How does the Consumer's Garden Grow?
  5. The Ins and Outs of Sour
  6. Maximizing the Quality of Salmon during Processing

Quite a number of consumers believe that organically grown vegetables are better for the consumer, and that they taste better. It's hard to develop any real information, as commercially grown vegetables may be grown from different cultivars, and may be harvested at different times. “Consumer Sensory Analysis of Organically and Conventionally Grown Vegetables” sought to take some of the variables out of the equation by growing rows of vegetables, and its authors, from Kansas State Univ., grew a variety of vegetables in high wall tunnels, so that the differences in cultivation and so on could be controlled. They used organic fertilizer at double strength on the organically grown crops to compensate for reduced accessibility by the organic plants. The results showed little difference in flavor between organic and conventionally grown vegetables (except in tomatoes, where the organic version ripened faster). However, consumers who liked organic better didn't seem to care much whether they tasted better or not. They preferred organic vegetables because they perceived them to be better for the environment. And they didn't seem to care if they cost more. p S87-91.

The Ins and Outs of Sour

  1. Top of page
  2. Where does the Flavor Go?
  3. Moving Beyond the Database
  4. How does the Consumer's Garden Grow?
  5. The Ins and Outs of Sour
  6. Maximizing the Quality of Salmon during Processing

“The Chemistry and Physiology of Sour Taste—A Review” by researchers from USDA and North Carolina State Univ. covers much of the available literature about the chemistry of sour tastes, including a table that suggests flavor profile for the various organic acids. As it has become clear that sour taste is complicated; new hypothesis have been developed, including one from the USDA labs: “Our laboratory recently developed a new hypothesis for the chemical basis of sour taste of organic acids, which proposed that sour taste intensity is a linear function of the total molar concentration of all organic acid species that have 1 or more protonated carboxyl groups plus the concentration of free hydrogen ions.” This hypothesis was based on correlations between sour taste intensity and the molar concentrations of protonated organic acid species and hydrogen ions in dill pickles, sauerkraut, and acid solutions analyzed from published datasets. Acids impart more than taste to foods, including olfactory and tactile sensations. Solutions of lactic, citric, malic, tartaric, sulfuric, hydrochloric, and phosphoric acids at high concentrations can be detected by nasal inhalation, apparently by the trigeminal nerve. Some organic acids, such as acetic, have a definite vinegar flavor, while others have a cheesy, citrus, tallowy flavor. Some inorganic food acids are more astringent than sour. Because the choice of a food acid has a strong impact on the final food, information in this review can be extremely helpful to food formulators. p R33-38.

Maximizing the Quality of Salmon during Processing

  1. Top of page
  2. Where does the Flavor Go?
  3. Moving Beyond the Database
  4. How does the Consumer's Garden Grow?
  5. The Ins and Outs of Sour
  6. Maximizing the Quality of Salmon during Processing

Researchers from Washington State Univ. studied the effects of retorting systems on the various parts of salmon muscle. The paper “Quality Changes of Salmon (Oncorhynchus gorbuscha) Muscle during Thermal Processing” studied the fillet muscle along the longitudinal axis of salmon fillets (raw and heated). The properties that were studied included shear force, color, cook loss, and shrinkage; changes between raw and heated salmon muscle were compared. A multiple thin blade texture device was developed for shear force measurement and a computer vision system used to facilitate accurate measurements of color and shrinkage. The red muscle was firmer than the white muscle in the raw but not in heated samples. Muscle from the central dorsal region had a lower cook loss and less shrinkage than samples from either the anterior or posterior region following heating. The changes that occurred were rapid, showing the greatest change in quality during the first few minutes of heating. The greatest change in quality occurred within the first 10 min of heating.

Canned salmon accounts for about 40% of the harvested salmon, which is provided as a shelf-stable food. Heat-induced protein denaturization causes shrinkage of the muscle fibers. A major problem has been to provide real information in the face of the difference between different parts of the muscle. To help find real information, the Washington researchers used a multiple thin blade (MTB) device to improve the ability top gain reliable muscle tenderness readings. A color vision system measured color and area changes of salmon muscle after heat treatments were performed. Shear force differed significantly along the length of raw salmon muscle, while color remained uniform. Most changes occurred within the first 10-min heating: the muscle color changed to the whitest, the shear force increased to the maximum, and 70% of total cook loss and shrinkage took place. The shear force profile had two peaks, with the first peak in the 5 min and second peak at 1-h heating time, indicating that longer heating did not necessarily tenderize the muscle texture further. p S103-111.