Showing papers in "Lwt - Food Science and Technology in 1990"

Fat uptake in a potato drying/frying process

Abstract: The fat uptake during deep fat frying of potato strips, French fries, was affected by the pretreatment and the frying time. The highest fat content was observed for blanched, undried potato strips. The surface moisture content seemed to be the limiting factor. The frying time also seemed to influence the fat uptake. During the frying process the drying rate was found to be higher at the beginning of the process. This observation was confirmed by a calculation of the mass transfer coefficients

Quinoa - composition, nutritional value, food applications.

Abstract: Quinoa has been an important grain crop in the Andes for many centuries, and now it is gaining popularity elsewhere in the world. In comparison with common cereals, quinoa is generally higher in protein, fat and fiber. Protein quality was shown to be high. Of equal importance is the hardiness of the plant. Unlike most other food crops, quinoa is drought resistant, grows at high altitudes and on poor sandy soil. Quinoa has one major shortcoming, however. It contains saponins, which are bitter and have antinutritional effects. To be edible, the grain must have the saponins removed. Quinoa has been used in many different food products. It has potential as an alternate crop for various areas of the world

Effects of water activity on textural characteristics of puffed rice cake

Abstract: The moisture sorption isotherm of puffed whole-grain brown rice cakes was established by equilibrating dehydrated whole cakes over saturated salt solutions and found to be sigmoid-shaped. The effects of water activity (a w ) on textural characteristics of rice cakes were determined using a breaking test. The textural characteristics (first peak force, maximum peak force and work done) of rice cakes can be separated into two groups: a w 0.23-0.44 and 0.57-0.84. a w 0.44 was a critical point as far as rice cake texture is concerned

Proteins of the phenolic extracted sunflower meal. 1. Simple method for removal of polyphenolic components and characteristics of salt soluble proteins.

Abstract: The objectives of the present study are to develop a method using a cheap and commercially feasible solvent system for the removal of polyphenolic compounds and to evaluate the changes in the sunflower's major proteins due to solvent extraction used for the removal of phenolic compounds

The formation of ternary inclusion complexes of starch with menthone and monostearate : a possible food model system

Abstract: The formation of inclusion complexes of gelatinized potato starch with the food grade emulsifier monostearate and with the flavor compound menthone was studied under equilibrium conditions in ternary model systems. The reaction was followed by a combination of amperometric iodine titration with GC analysis of the complex partners. X-ray analysis of the ternary complexes was conducted in order to identify the helical conformations of amylose in these complexes. Binding isotherms, approximated by the Hill equation, were analysed by the «affinity spectrum method» and binding parameters were estimated by means of regression methods

Determination of Fickian diffusion coefficients of water in foods using NMR-techniques and the DARKEN-equation.

Abstract: Fickian diffusion coefficients of water in slices of potato tissue were calculated using the DARKEN-equation: Self-diffusion coefficients, D S , were determined by NMR-techniques while moisture content X and water activity, a w , were obtained from the sorption isotherm. The results agree with the principle features of direct measurements of D F , from the literature, showing a maximum of D F for moisture contents where multilayer adsorption changes to capillary condensation. The method was applied to potato slices. It can, however, be easily transferred to other food products

Analysis of boiled crab meat flavour: identification of new alcoholic constituents.

Abstract: Nineteen alcohols have been identified in a crab extract, two of them being discovered for the first time in a food system: 3,5,5-trimethyl-1-hexanol, and 1-methyl-cycohexanol

Alkylresorcinols in cereal grains - nutritional importance and methods of analysis.

Abstract: The occurrence of 5-n-alkylresorcinols (AR) in various plants is of great interest. ARs in cereal grains were shown to inhibit growth in several animal species. These compounds are present in the highest amount in rye, in lower amounts in wheat and triticale and in small quantities in other cereals. Milling of wheat, rye and triticale into bran, shorts and flour indicated that bran contains the highest, shorts intermediates and flour the lowest amount of ARs. The study of these compounds in human food an how they are affected by food processing is very limited. Their effects in human nutrition are being tested. ARs were shown to cause red blood cell haemolysis, permeability changes of erythrocytes and liposomes, DNA stand scission. Structurally ARs are considered to be phenolic lipids an related to other phenolic lipids isolated from Anacardiaceae which process well known skin irritating and sensitizing activities. They are also similar in structure to flavonoids which possess antioxidant or free radical scavenging properties

Assessing the use of additives in food: a reappraisal of the Danish budget method

Abstract: It is the purpose of the present article to discuss the value and the limitations of the Budget Method. Taking sweeteners as an example, it is shown that the Budget Method may be used to differentiate between compounds which qualify for a GMP regulation and those which require an allocation of maximum limits of use. However, some adjustments of the original Budget Method may be required for such calculations in order to take more recent data on food intake and food additive use into account

Effect of potato composition on drum dryer capacity.

Abstract: A model for predicting the production capacity of a single drum dryer for potato flakes was developed. The model uses process parameters for drum speed, steam pressure and number of spreader rolls. It also includes the texture of the raw potato, degree of cooking, starch content of the raw potato and the bulk density of the dried raw potato. The model accounted for variation observed due to cultivar and production year

Use of a lysine oxidase electrode for lysine determination in Maillard model reactions and in soybean meal hydrolysates

Abstract: As an alternative to the classic ion-exchange chromatography for lysine determination, a new specific enzymatic method based on the use of lysine oxidase was developed. Results obtained on Maillard model reactions and on samples from soybeam meal hydrolysates are described. The levulinic acid formed from acid degradation of glucose was shown to negatively affect lysine determination. Different hydrolysis conditions were examined for soybean meal

Moisture adsorption characteristics and storage stability of rice bran protein concentrate.

Abstract: Water activity and equilibrium moisture data of full-fat and defatted rice bran protein concentrate powder at a fixed temperature of 27°C were obtained from apparatus designed for the purpose. The data were analysed for the determination of values of bound water, water activity for the maximum stability, moisture content at the change over points in the nature of moisture binding and energy required for the removal of bound water in these materials. BET, Caurie, Stability, «Local», and «GAB» isotherm models were used for analysing the data. Rice bran protein concentrates were found to be stable for storage in the water activity ranges of 0.2 to 0.4 and 0.35 to 0.36, which correspond to the equilibrium moisture contents of 2.8 to 3.8 and 3.2 to 3.7% respectively, for full-fat and defatted samples

Protein quality of tamarind and African locust bean seed meals.

Abstract: Twenty male weanling rats were divided into four groups of five rats each. One group was fed a protein-free diet. The other groups were fed diets in which casein, fermented Tamarind, or African Locust bean seed meals provided 10% crude protein for 28 days. The results showed that although rats fed casein. Locust bean or the protein-free diets consumed about the same amounts of feed, the rats fed casein showed significant weight gains use of Tamarind and Locust bean seeds would require improved cropping and preparation methods, necessitate modifications of the traditional methods of fermenting the seeds, and the breeding of new varieties which were toxin free and had low fiber and high protein contents