Daryl Lund

Influence of time, temperature, moisture, ingredients, and processing conditions on starch gelatinization

Starch gelatinization phenomena is extremely important in many food systems. This review focuses on factors affecting gelatinization characteristics of starch. Important variables which must be considered in design of processes in which starch undergoes gelatinization are heat of gelatinization and temperature of gelatinization. Major interactions are reviewed for the effects of lipids, moisture content, nonionic constituents and electrolytes on these characteristics. Furthermore, treatment of starch-containing systems prior to heating into the gelatinization temperature range can have a significant effect on ultimate gelatinization characteristics.

Effects of temperature and time on mutagen formation in pan-fried hamburger

Mutagenic activity generated in hamburger during pan-frying is dependent upon both temperature and time, with temperature appearing to be the more important variable. Uniformly prepared frozen hamburger pattie (115 g; 19% fat) were fried under carefully controlled conditions at 143 degrees C, 191 degrees C and 210 degrees C. Mutagenic activity assayed with the Ames test was not detected in uncooked hamburger, and in hamburger fried at 143 degrees C mutagenic activity remained low at all times studied (4--20 min). In contrast, frying at 191 degrees C or 210 degrees C for up to 10 min resulted in the generation of considerably higher levels of mutagenic activity. Mutagenic activity in fried hamburgers sold at selected restaurants ranged from very low to moderately high. Evidence is also presented for mutagenic inhibitory activity in uncooked and fried hamburger. Mutagenic inhibitory activity decreased mutagenesis mediated by liver S-9 from normal rats but not from Aroclor 1254-treated rats.

Food dehydration by solar energy

Solar driers that are currently being investigated for drying of agricultural products can be divided into two major divisions, depending upon how they transfer the incident solar energy to the product to be dried. These two divisions are direct and indirect drying, with some work also being done on combination drying procedures. In direct solar driers, the product to be dried is usually either inside a tent, greenhouse, or a glass-topped box, where the product to be dried is heated by the direct rays from the sun and the moist air is removed by ambient wind movement. These dryers do accelerate moisture loss rate and the product is usually safe from inclement weather. These dryers usually do not require fans for forced air circulation. With indirect drying, the opposite is true, where most require powered fans for forced air circulation. With this type of dryer, both flatplate and inflated tube solar heat absorbers are used, with each offering certain advantages. Also, combination dryers have been built that utilize both direct and indirect principles. Product evaluation of solar dried foods indicate that in most cases the physical properties, flavor, and vitamin A and C retention were as good as, or better than, conventional dried foods. The economics of the solar systems indicate that most drying procedures are economically feasible for use in small-scale operations only, with the exception of grain drying.

Predicting the impact of food processing on food constituents

With the advent of improved analytical techniques, statistical experiment design, computers and knowledge of food constituents, there have been significant advances in our knowledge of the impact of processing on food constituents. Unfortunately some of this information has not contributed significantly to our ability to predict the influence of processing or resulted in refined predictive equations. This paper reviews our current ability to predict the influence of processing on food constituents. Traditional and potential processes are examined and research needs are identified so that food quality quantification and prediction advances.

Handbook of Food Engineering, Second Edition

Food engineering Daryl B. Lund University of Wisconsin-Madison. Foodproteins/food 73 Handbook of Indigenous Fermented Foods Second Edition, Revised. Food Engineering Handbook: Food Engineering Fundamentals provides a stimulating and up-to-date review of food engineering phenomena. Combining theory. Transport and storage of food products, in “Handbook of Food Engineering,” eds. and uses, in Food Polysaccharides and Their Applications: Second Edition.

Cleaning and characterization of stainless steel exposed to milk

Abstract Cleanliness criteria for a milk-stainless steel interface system were established by monitoring the elemental composition of the stainless steel surface by Auger electron spectroscopy. A reproducible chemical cleaning procedure to remove milk deposits from the surface was designed. If UV-ozone exposure of the chemically cleaned surface was included as a last step in the cleaning procedure, the amount of contaminants (as carbon) present at the surface was further reduced. Argon sputtering of the surface showed that the contaminants were confined to a surface layer 5 nm thick of the stainless steel plate. Chemically cleaned plates could be stored in Petri dishes in a desiccator for up to 56 days without significant recontamination as measured by the carbon content on the surfaces. However, storage in air resulted in gross recontamination of the surface within a few hours. Scanning and transmission electron microscopy were used to examine the surfaces of cleaned stainless steel plates and the topography of milk deposits attached to the plates. Preparation procedures for these special applications were developed.

Wild rice: The Indian's staple and the white man's delicacy

Wild rice (Zizania aquatica) is an annual aquatic grass which grows in shallow lakes, marshes and in sluggish streams in various parts of the world. The grain of wild rice has been harvested by the Indians of the United States and Canada for many centuries. Explorers entering the territories of the Northern Lake States of America a few centuries ago described wild rice as a spontaneous crop which does not require plowing or sowing providing an abundant harvest of palatable and nourishing grain. Natural propagation assured the Indians of a yearly crop. As time passed, wild rice lost its importance as a staple for the Indian population, but it became a white mans delicacy because of its unique color and flavor characteristics. In the U.S. a commercial wild rice industry developed. The grain is now found on supermarket shelves, but at a rather high price compared to prices for other cereal grains. Today, most of the wild rice in the world is harvested as a cultivated crop from paddies in the state of Minnesota. Smaller amounts are produced in Wisconsin and in southern Canada. Wild rice has some desirable nutritional attributes. Its protein content is relatively high compared to other cereal grains. Wild rice is a good source of the B vitamins, thiamin, riboflavin and niacin and contains common mineral elements in amounts comparable to those in oats, wheat and corn. Wild rice is used as a main meal ingredient in regular or quick cooked form and has numerous possible secondary usages. Because of its good nutritional balance wild rice could help to provide another source of energy and quality protein for the diet of man.

The Beginning, Current, and Future of Food Engineering: A Perspective

Food engineering as a discipline is still evolving, and therefore, is developing in various ways in different parts of the world. Much of the documented evolution in both food engineering research and education has occurred in the past 50–75 years. Educational programs in food engineering have been developed at many institutions throughout the world. The origins of these programs can be traced to the 1950s and currently the curricula continue to evolve. Some programs are for degrees in food engineering, while others illustrate the increasing role of food engineering in undergraduate and graduate programs leading to degrees in food science.

Differential scanning calorimetric model for corrections to the DSC record

Abstract Based upon the signals of a DSC record, the equation of the transition baseline is analytically developed for a DuPont 990 thermal analyzer. The equation accounts for the effects on the transition baseline originating from (1) pretransition baseline, (2) heat-capacity change from that of the reactants to that of the products of reaction and (3) the fact that the sample material is subject, during the transition state, to a heating rate which differs from that of the reference material. If there is no change in heat capacities and either the heating rate or the heat transfer resistance are very small, then the transition baseline is merely an extension of the pretransition baseline. Any departure from these conditions makes the calculation of the transition baseline necessary, if correct kinetic parameters are to be expected from a DSC curve.

Rate of Precipitation of Calcium Phosphate On Heated Surfaces

Fouling of a heated stainless steel surface by calcium phosphate precipitation has been studied in an annular flow apparatus, instrumented to provide a constant heat flux while measuring local metal‐surface temperatures. Models of the heat and mass‐transfer boundary layers are used to estimate interfacial temperatures and concentrations, from which the heterogeneous reaction rate is inferred. The analysis indicates that the reaction rate is a function of both chemical kinetics and mass transfer limitations.