Native black Michuñe potato variety: characterization, frying conditions and sensory evaluation

The aim of this study was to evaluate the chemical and nutritional composition, to establish frying processing conditions and to determine the sensory profile and acceptability of Black Michuñe (BM) potato chips. BM had a higher protein content, half the ether extract content and nitrogen-free extract, a lower caloric intake (70 kcal/100g) and amylose content (17.5%) than Desirée (DES). To set the frying conditions, the Taguchi method was applied using a matrix design L9 (3(2),2(2)). The variables studied were: temperature, time, potato variety (raw material) and pretreatment. The responses evaluated were: the color difference as well as the content of reducing sugars and total polyphenols. The best frying conditions were BM with a pretreatment at 160 degrees C for 7 min for color, DES without pretreatment at 140 degrees C for 7 min for reducing sugar content, and BM without pretreatment at 180 degrees C for 4 min for polyphenol content. Then, sensory profiles of potato chips from BM, DES and a commercial package were determined by selecting the descriptors texture, firmness, color, salty taste and oiliness. Significant differences in color and oiliness were found. Finally, the acceptability test was applied to BM potato chips where color (64%) was the only attribute not as accepted as texture (95%), salty taste (87%) and product (97.3%). This study demonstrated that BM potato chips have a satisfactory acceptability by consumers.

[Fat substitutes in human diet]

Fat consumption in developed countries has increased steadily during this century reaching values higher than 40% of the daily total calorie intake. This situation has resulted in a high prevalence of obesity, cardiovascular disease, diabetes and some types of cancer. The health agencies in these countries have made strong recommendations for the population to reduce dietary fat intake in order to reduce total fat intake to les than 30% of the total calories, with a maximum of 10% calories derived from saturated fats. The food industry has taken a very active role developing a number of low fat foods and opening a new area of products called fat substitutes in order to help the consumers reduce their fat consumption. One of these substitutes is a synthetic product obtained by reacting fatty acids from natural sources and sucrose. The product is a polyester of sucrose and has been named olestra. Olestra has been approved by the US Food and Drug Administration (FDA) to be used in snacks and fried chips. Due to its lipophilic nature olestra has a negative effect on the absorption of fat soluble vitamins and nutrients. However, this problem may be solved by supplementation of the nutrients affected. In addition, olestra may cause gastrointestinal effects such as abdominal cramping and stool softening. The Company that developed olestra claims to have solved this problem by modifying the composition of fatty acids of the product. Olestra is being marketed in the USA under the name of Olean.

[Iodine nutrition in school children of four census areas of Chile]

BACKGROUND

Although endemic goiter is an easily controlled chronic disease, it continues to be a serious global public health problem.

AIM

To study iodine nutrition in school age children from different areas of Chile.

SUBJECTS AND METHODS

Thyroid gland was palpated in 4181 school age children from Calama, Santiago, Temuco and Punta Arenas. Urinary iodine excretion was measured to 9% of these children and iodine concentration in salt for human consumption obtained in each of these areas was determined.

RESULTS

A 9% goiter prevalence in boys and 11% prevalence in girls was detected. The prevalence of goiter Ia was 6.5% and the figure in different geographic areas was similar. Iodine concentration in salt for human consumption was adequate according to Chilean legislation (82.6, 95.7, 96.8 and 93.2 micrograms ugI/g salt in Calama, Santiago, Temuco and Punta Arenas respectively). Urinary iodine excretion in boys and girls was 1695 and 1802 micrograms l/g creatinine in Calama, 680 and 732 in Santiago, 574 and 690 in Temuco, 570 and 528 in Punta Arenas. These values are well above recommendations.

CONCLUSIONS

Endemic goiter is no longer a problem in Chile. The importance of a continuous surveillance of iodine nutrition in Chile and the reduction of salt iodine concentration required by Chilean legislation is underscored.

[Chemical, sensory and clinical characterization of lupin marmalades]

Legumes are characterized as showing interesting hypoglicemic properties. Their presence in the diet is very useful in controlling the level of blood glucose in diabetic people. Taking in mind this property different formulations of prune marmalades were developed using 5, -7.5, 10 and 15% of full fat sweet lupin flour (FFLF). These samples were submitted to chemical, physical, sensory and clinical analysis. The protein content increased from 0.6 to 5.2% in direct proportion to lupin flour concentration. Energy content remained relatively constant in all formulations. The incorporation of FFLF did not affect the natural dark red prune color and pH, acidity and soluble solids values remained under the limits of Chilean food regulation laws. The samples were analyzed by a Rank preference test. Reported data showed a significative preference for the prune marmalade with 10% HEL (p < 0.05). A facial Hedonic test was used to compare the degree of acceptability between this formula and a control marmalade with fructose as edulcorant. Statistical analysis using the student test did not show significant difference (p < 0.05) between them. The hypoglycemic effect of the lupin flour was tested in seven adult non insulin dependent diabetic patients using the glucose tolerance test. Postprandial blood glucose concentration data was lower in individuals after a test meal of lupin marmalade compared to fructose marmalade. This result would allow diabetic people to eat foods such as marmalades which are known to contain a large amount of carbohydrates.

[Sensory characterization of lupin pudding using surface response methodology]

Full fat sweet lupin flour (Lupinus albus c.v. Multolupa) with 39.6% protein and 13.0% lipid content, and carrageenan were used to incorporate them to commercial pudding formula with the specific purpose to prepare an optimized pudding for diabetic people. Using response surface methodology, several experimental pudding trails were prepared and sensorially assessed to optimize the variables that may influence the overall sensory quality of pudding meals. Different concentrations of lupin flour and carrageenan were tested simultaneously at three levels each parameter, requiring nine combinations to be analyzed for a panel of eleven trained judges. Appearance, aroma, taste, color, texture were tested to determine total sensory quality using a composite scoring test. It was concluded that appropriate concentration of lupin flour range from 7% to 11%, and carrageenan from 0.4% to 0.5% to be added to the pudding formulation. This result was confirmed by hedonic test of acceptability.

Characterization of Chilean hazel nut sweet cookies

A series of studies were carried out to test the effect of the incorporation of Chilean hazel nut flour in sweet cookies at the levels of 0%, 5%, 10%, 15% and 20%. The proximate chemical analysis of the different flour mixtures showed a regular increase from 7.2 to 12.2%, 14.5% to 18.8% and 1% to 2.2%, respectively, decreasing at the same time with the percentages of water and carbohydrates. Chemical amino acid scores of leucine and threonine in wheat flour improved with the incorporation of Chilean hazel nut flour. The farinographic evaluation made to the different blends showed several changes occurred with the incorporation of Chilean hazel nut flour to wheat flour. These included increase in water absorption, decrease in dough developing time and weakening of the dough. Sensory characteristics such as appearance, texture, flavor and also acceptability improved with the incorporation of Chilean hazel nut flour into the cookie formulas.

[Protein complementation of defatted hazelnut flour with pea flour]

A great deal of research has been carried out to increase the availability of naturally-occurring proteins, or obtained from secondary products derived through industrial processes. As a result of the industrial exploitation of the native hazelnut (Gevuina avellana) in Chile, a defatted residue is obtained which eventually could be utilized as a human food. To determine the complementary potential capacity of the defatted hazelnut flour and pea flour, a study was carried out in weaning rats of the Wistar strain, as follows. The biological evaluation considered diet formulation with defatted hazelnut flour and pea flour in the 30:70, 50:50, 60:40 and 70:30 proportions, respectively. The NPR values obtained in this evaluation of the assay diets were: 3.4, 3.5, 3.9, 4.1 and 4.1, in comparison with 3.7 for casein. In percentage terms, the 4.1 NPR value was 11% higher than that obtained for casein. The maximum protein quality was observed when the two protein sources were mixed in the 60:40 and 70:30 (w/w) ratios. In regard to true digestibility, there were no significant differences among the experimental diets, but were lower than casein. The results of this study demonstrate that the defatted hazelnut flour constitutes an attractive nutritional alternative for the amino acid supplementation of cereal and legumes, the latter being of habitual consumption by the Chilean population.

[Prevalence of endemic goiter among school children of central and southern Chile]

The prevalence of endemic goiter was evaluated during 1986 in 1,015 school age children from basic public schools of Santiago and Temuco, Chile. The prevalence of goiter, defined by WHO's standards was 7.6% as a whole, without differences related to children's geographical origin. A greater prevalence of goiter, in females than in males, which increased with age, was detected. Prevalence of endemic goiter decreased from year 1982 to year 1986 from 18.8% to 7.4% in similar samples of school children from Santiago. This change may be due to preventive iodination of table salt.

[Chemical composition and biological quality of defatted hazelnut flour]

The results of the chemical composition and biological quality of deffated hazel nut flour are shown. The samples analyzed contained significant amounts of proteins (19%) comparable to legume flour, higher than cereals and lower than deffated oleaginous flours. The oil extracted from the seed was analyzed and the average results obtained were the following: Refraction index, 1.47; saponification No. 184.8; iodine No. 85.0. The average composition of the fatty acids obtained by gas liquid chromatography was: Palmitic acid 2.3% Palmitoleic acid 37.0% Stearic acid 0.5% Oleic acid 39.5% Linoleic acid 6.9% Linolenic acid 1.1% Eicosanoic acid 2.3% Eicosaenoic acid 4.6% Docosenoic acid 3.4% Tetraeicosanoic acid 0.3% These results indicate a good-quality oil due to the low content of linolenic acid. The nutritive value of the deffated meal measured in the rats gave a net protein ratio (NPR) of 3.58, lower than the corresponding casein value (4.10). The true protein digestibility measured in the rat gave a value of 7.3%, compared to 95% for casein. The amounts of iron and phosphorous are comparatively lower than those reported for rape-seed meal and sunflower meal.