Wheat Starch Pasting Measured with a “Minipaster”

A Minipaster apparatus, based on a Haake Rotary Viscometer, was developed to investigate thermal pasting of aqueous starch suspensions, and to study the effects of varying heating rate, holding time and holding temperature, and of varying starch concentration. Comparison has been made with a Brabender Visco-amylograph. Attention is drawn to the marked serial dependence of the simple pasting parameters, peak viscosity temperature, peak viscosity, breakdown viscosity and setback viscosity. Relative breakdown and setback, and various ratios of pasting parameters are not markedly superior to the simple parameters as discriminants between starches.     

Structure of Starch from Mango Seed

Starch was isolated from fresh mango seed kernels. The effect of glucoamylase-α-amylase on the granule ultrastructure was evaluated by scanning electron microscope. Amylose and amylopectin were isolated and their molecular structures were studied, using enzymic methods, HPTLC, and gel permeation chromatography. The structure of amylopectin was similar to amylopectin of other starches. The shortest branch chain had 6 glucose units. Amylose had a ß-amylolysis limit of 77%. In order to improve solution stability during debranching with pullulanase and chromatography, amylose was partially acetylated. The debranchin of the unmodified and modified amyloses produced a 15–25% decline in the limiting viscositiy number and a slight shift in the molecular size distribution. These results are consistent with the concept that a fraction of the amylose molecules have limited branching and that these branched chains contain a significant number of glucose units.     

Effect of starter species on the content of some volatile aromatic compounds of kashkaval “Balkan” and kashkaval “Vitosha”

Four kinds of starter cultures created in this country were used for production of kashkaval “Vitosha” and kashkaval “Balkan”. In the process of ripening and storage of the products the changes of some aroma compounds taking part in flavour formation were followed besides acidity, pH and percentage of sodium chloride. Two of the aroma compounds, i.e. diacetyl and ethanol, were of outstanding importance for the quality of kashkaval “Vitosha”, whereas in respect to kashkaval “Balkan” such a relationship was not established. Inference was drawn that the product's flavour was dependent on starter culture and kind of milk.     

Impact of Annealing on the Physicochemical Properties of Unfermented Cassava Starch (“Polvilho Doce”)

Unfermented cassava starch (“polvilho doce”) was subject to annealing treatment at 50°C for 24, 48, 96, 120, 168 and 192 h, in 1:5 starch to water ratio. The annealing treatment changed the internal structure of “polvilho doce” at increasing treatment time. Peak viscosities decreased significantly, denoting that there was a decrease in leaching of amylose from the granules. The pasting temperatures were increased, setback and breakdown were reduced while hold and final viscosities increased, showing an improvement of the stability of the paste. Swelling power and solubility were reduced at all temperatures and the solubility at 55°C was zero after 120 h of treatment. The DSC data for T_o, T_p, T_c and ΔH increased and the gelatinization range was narrowed. The X‐ray diffractograms changed from C_A to A pattern (samples annealed for 48, 96, 120, 168 and 192 h), denoting an increase in organization of double helices of amylopectin. Annealing imparts to the samples some waxy starches characteristics which can be very useful in the food industry.     

Versorgung mit “sanften” Energien — eine Utopie

Living on “Soft” Energies – a Utopia. Pure utopia and a way to “dictatorship of puritanism”, so three scientists from the nuclear research plant in Juelich recently said, was what the “Greens” have claimed to be the target for the next fifty years: the conversion of our society to “soft” ernergy supply.     

Microbial quality of “doubles” sold in Trinidad

A cross-sectional study was conducted to determine the prevalence and characteristics of Escherichia coli, Staphylococcus aureus, Bacillus spp. and Salmonella spp. in “bara”, “channa”, condiments/spices and ready-to-eat “doubles” sold by vendors in the St. George and Caroni counties of Trinidad. Of 196 samples of each of “bara”, “channa”, condiments/spices and ready-to-eat “doubles” examined, E. coli was detected in 0 (0.0%), 14 (7.1%), 96 (49.0%) and 67 (34.2%), respectively; Staphylococci were isolated from 104 (53.1%), 71 (36.2%), 129 (65.8%) and 123 (62.8%) samples, respectively; and Bacillus spp. were recovered from 22 (11.2%), 85 (43.4%), 100 (51.0%) and 88 (44.9%) samples, respectively. Salmonella spp. were not isolated from any sample. Of the 177 isolates of E. coli recovered from all sources, 9 (5.1%), 7 (4.0%) and 47 (26.6%) were mucoid, haemolytic and non-sorbitol fermenters (NSF), respectively, but none agglutinated with O157 antiserum. Of 427 staphylococcal isolates, 130 (30.4%) were confirmed as S. aureus of which 20 (15.4%) were haemolytic and 84 (64.6%) pigmented, while 17 (20.7%) of 82 strains of S. aureus tested produced enterotoxins. Ready-to-eat “doubles”, a popular food in Trinidad, therefore pose a potential health risk to consumers due to the high level of contamination with bacteria.     

Impact of Microclimate on Fatty Acids and Volatile Terpenes in “Kerman” and “Golden Hills” Pistachio (Pistacia vera) Kernels

Pistachio is an economically important nut crop in California. Since temperature variations among geographical locations can influence biochemical processes during fruit development, it is of great relevance to understand the impact of growing area over the components that define the nutritional and sensory characteristics of pistachio nuts. Changes in moisture, fat content, fatty acid composition and volatile terpenes were studied during kernel development for “Kerman” and “Golden Hills” varieties in two different California Central Valley microclimates, Lost Hills and Parlier. Moisture content decreased from July to September for both cultivars at both locations. Kerman had a higher moisture content at both locations compared with Golden Hills. Harvest time affected fat content only for Kerman, where the values increased drastically from 21‐July to 4‐Aug, then remained constant. Golden Hills’ fat content remained constant during the period of the study. The main fatty acid in pistachio oil is oleic acid (46% to 59%), followed by linoleic acid (26% to 36%) and palmitic acid (11% to 16%). C16:0, C16:1, C18:2, and C18:3 decreased with harvest time, while C18:1 increased. α‐Pinene was the most concentrated volatile among the cultivars and locations. It decreased with harvest time for both cultivars at both locations, ranging from 105 to 2464 mg/kg. At harvest, Golden Hills and Kerman at Parlier both had higher concentrations of α‐pinene than the two cultivars at Lost Hills. Our results demonstrate that microclimate affects biosynthesis of fatty acids and terpenes in pistachio kernels, the main compounds responsible for pistachio nutritional and sensory characteristics.     

Scombroid poisoning. Isolation and identification of “saurine”

A number of samples of fish which were involved in allergy-like food poisoning incidents were examined for the presence of “saurine”, a toxin reported to be the causative agent in scombroid poisoning. Chromatograms of extracts developed in acidic solvents showed two distinct areas which possessed vagal stimulating activity with guinea pig ileum. Both these areas contained histamine and this suggests that “saurine” is a histamine salt.     

Microalgae for “Healthy” Foods—Possibilities and Challenges

Abstract: Microalgae have the potential to become a novel source of bioactive molecules, especially for those who might wish to enhance the nutritional and functional quality of foods. Spirulina, one of the most popular microalgae, has been described by the World Health Organization as one of the greatest superfoods on earth serving as an example of the potential of microalgae. This review provides background on current and future uses of microalgae in the human diet, lists the most common species of microalgae used to this end, and describes some production methods used in research and industrial production and recovery. The review also discusses some of the difficulties so far encountered such as low productivities and recovery rates, as well as challenges in the production of compounds of interest. Many scientists and engineers in research centers around the globe are currently dedicated to solve these problems as the various capabilities of microalgae have caught the attention of the energy, environmental, and agricultural industries, we propose that the food industry should as well evaluate the potential of microalgae as a novel source of “health promoting” compounds.     

An Objective Illustration of the Inadequacy of the Official EC “Ewers” Method for the Determination of Starch

The Ewers method for starch determination is currently the Official EEC method for measurement of starch purity. In this communication we demonstrate that the use of trifluroacetic acid for solubilisation of starch prior to polarimetric measurements is preferred over the use of mineral acids since the degree of hydrolytic degradation observed with this reagent was minimal compared to mineral acids, thereby giving improved starch purity values. Of particular concern we demonstrate that the Ewers method is non-specific in that the addition of an epichlorohydrin cross-linked dextran as an adulterant enhances the value of starch purity obtained. The Ewers method however was able to detect agarose and carboxymethyl cellulose added to starch as adulterants. It is concluded that the Ewers method is not an acceptably satisfactory method for starch purity measurement on which to base quality control or eligibility for rebate and refund schemes.     

A Critical Assessment of the Parameters Affecting the Official EC “Ewers” Method for the Determination of Starch

The Ewers method for the measurement of starch is currently the official EEC method for the measurement of starch purity. In this communication a critical assessment of variables affecting the Ewers method has been undertaken. It was found that the degree of hydrolytic degradation which occurs during the solubilisation of starch prior to polarimetric measurements is of crucial importance in the starch purity values obtained. Factors which influence the degree of hydrolytic degradation include hydrochloric acid concentration to a large extent, and heating and cooling times to a lesser extent. It has been shown also that the clarifing reagent of Carrez, which is used in Ewers method for the removal of other chiral molecules such as protein, etc, adsorbs lower molecular weight malto-oligosaccharides leading to reduced starch purity values. For a series of starches with varying amylose: amylopectin ratios it was found that high amylopectin starches performed much better in Ewers method than high amylose starches. It is concluded that Ewers is not an acceptable satisfactory method for starch measurement on which to base quality control or eligibility for rebate and refund schemes.