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The texture of tortillas was improved by the addition of maltogenic amylase and carboxymethylcellulose (CMC) and guar gum to fresh masa from ground nixtamal (FNM) and nixtamalized corn flour (NCF) masa. Differences in the performance of additives in tortillas held under refrigeration or ambient storage were documented. For NCF tortillas, significant improvements were obtained in objective and subjective texture measurements by two treatments. Tortilla texture was improved by a treatment with a high enzyme level (170 mg/kg of maltogenic α-amylase, 0.14% CMC, 0.85% guar) as measured by objective tests and by a treatment with low enzyme level (60 mg/kg of maltogenic α-amylase, 0.43% CMC, 0.57% guar) as measured by subjective tests. The addition of maltogenic α-amylase (70 mg/kg) and CMC (0.35%) to FNM tortillas at levels similar to the low enzyme NCF treatment but with lower guar level (0.12%) improved tortilla texture. The maltogenic α-amylase softened tortillas by trimming the starch structure. This allowed the guar to interfere with amylopectin re-crystallization inside gelatinized starch granules. The CMC created a more flexible intergranular matrix that helped maintain the disrupted tortilla structure. Guar was ineffective in refrigerated tortillas, whereas, maltodextrins effectively improved refrigerated tortillas. The sequence of partial starch hydrolysis, warm holding condition, and time for guar to associate with starch and CMC was necessary to improve tortilla texture. Thus, different additives may be required for cold versus room temperature storage. Sugars increased in enzyme-treated tortillas during storage. This suggests that maltogenic α-amylase was only partially inactivated during baking of corn tortillas. Tortillas with more enzyme had lower and later pasting viscosity as measured by a Rapid Viscoanalyzer. Tortillas prepared from FNM also had lower and later pasting viscosity compared to NCF tortillas. Pasting viscosity of tortillas revealed intrinsic starch polymer characteristics and interactions. Results of this study provide commercially applicable information about desired levels for the extent of starch hydrolysis, the type and amount of gums and starches, and product microstructure to delay staling of corn tortillas.

No description available.

Three saponin-rich extracts (20, 60, 100% methanol), four 100% methanol subfractions and seven independently acquired fractions (A-G) from guar meal, Cyamopsis tetragonoloba L. (syn. C. psoraloides), were evaluated for antimicrobial and hemolytic activities. These activities were compared against quillaja bark (Quillaja saponaria), yucca (Yucca schidigera), and soybean (Glycine max) saponins in 96-well plates using eight concentrations (0.01 to 1.0 and 0.1 to 12.5 mg extract/mL). Initial guar meal butanol extract was 4.8 ± 0.6% of the weight of original material dry matter (DM). Butanol extract was purified by preparative reverse-phase C-18 chromatography. Two fractions eluted with 20, and one each with 60, and 100% methanol with average yields of 1.72 ± 0.47, 0.88 ± 0.16, 0.91 ± 0.16 and 1.55 ± 0.15% of DM, respectively. Further purification of the 100% methanol fraction using normal-phase silica gel preparatory high pressure liquid chromatography eluted 4 peaks at 16, 39, 44 and 46 min. Only the 100% methanol fraction, its 16 min peak, F and G fractions, and quillaja saponin, exhibited both hemolytic and antibacterial activities against Staphylococcus aureus, Salmonella Typhimurium and E. coli, but 20 and 60% methanol fractions stimulated Lactobacillus spp. growth. Guar meal (0 or 5%) was added to diets fed to chicks from 1 to 21 days of age. Chicks fed both diets were unchallenged or challenged with 5 x 103 Eimeria tenella sporulated oocysts at 10 days. Guar meal diets reduced oocysts shed per gram of feces, body weight, and feed efficiency. Adding 2.5% guar meal, 1% guar gum, or 0.125% saponin-rich guar meal extract to diets fed to chicks to 21 days of age showed that guar meal increased the cfu concentrations of digesta more than controls following a challenge with 107 cfu of Clostridium perfringens at 14 days. Body weights of chicks fed guar meal and saponin-rich extract were significantly lower than control body weights at 21 days of age, whereas the weekly feed to gain ratio of chicks fed saponin-rich extract was higher than controls. Guar meal reduced severity of Eimeria tenella infection and guar saponin-rich extract exhibited antimicrobial activity against several common poultry pathogens.

The texture of tortillas was improved by the addition of maltogenic amylase and carboxymethylcellulose (CMC) and guar gum to fresh masa from ground nixtamal (FNM) and nixtamalized corn flour (NCF) masa. Differences in the performance of additives in tortillas held under refrigeration or ambient storage were documented. For NCF tortillas, significant improvements were obtained in objective and subjective texture measurements by two treatments. Tortilla texture was improved by a treatment with a high enzyme level (170 mg/kg of maltogenic α-amylase, 0.14% CMC, 0.85% guar) as measured by objective tests and by a treatment with low enzyme level (60 mg/kg of maltogenic α-amylase, 0.43% CMC, 0.57% guar) as measured by subjective tests. The addition of maltogenic α-amylase (70 mg/kg) and CMC (0.35%) to FNM tortillas at levels similar to the low enzyme NCF treatment but with lower guar level (0.12%) improved tortilla texture. The maltogenic α-amylase softened tortillas by trimming the starch structure. This allowed the guar to interfere with amylopectin re-crystallization inside gelatinized starch granules. The CMC created a more flexible intergranular matrix that helped maintain the disrupted tortilla structure. Guar was ineffective in refrigerated tortillas, whereas, maltodextrins effectively improved refrigerated tortillas. The sequence of partial starch hydrolysis, warm holding condition, and time for guar to associate with starch and CMC was necessary to improve tortilla texture. Thus, different additives may be required for cold versus room temperature storage. Sugars increased in enzyme-treated tortillas during storage. This suggests that maltogenic α-amylase was only partially inactivated during baking of corn tortillas. Tortillas with more enzyme had lower and later pasting viscosity as measured by a Rapid Viscoanalyzer. Tortillas prepared from FNM also had lower and later pasting viscosity compared to NCF tortillas. Pasting viscosity of tortillas revealed intrinsic starch polymer characteristics and interactions. Results of this study provide commercially applicable information about desired levels for the extent of starch hydrolysis, the type and amount of gums and starches, and product microstructure to delay staling of corn tortillas.

Orientador: Valdemiro Carlos Sgarbieri / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-21T22:27:49Z (GMT). No. of bitstreams: 1 Frias_AndreaCristinaDario_D.pdf: 4059789 bytes, checksum: 17b28b7aa31ed310bdccc478a4122e2f (MD5) Previous issue date: 1996 / Resumo: Goma guar, derivada do endosperma de sementes de Cyamopsis tetragonoloba foi utilizada nesta pesquisa sendo formada de 75% de fibra solúvel, 7,6% de fibra insolúvel, 2,16% de proteína bruta, 0,78% de lipídios totais, 0,54% de cinza e 9,55% de umidade. O tamanho das partículas (granulometria) e a viscosidade da goma utilizada durante os ensaios, foram determinadas. Quanto ao tamanho das partículas, verificou-se que 98,6% foram menores que 200?m. A viscosidade foi influenciada pelo pH e tempo de hidratação, sendo que a goma guar apresentou uma viscosidade 8 a 10 vezes mais elevada que a da pectina, fibra solúvel utilizada para efeito comparativo. A viscosidade máxima da goma guar (3,64 Pa.s) foi obitda em pH 8,0 e com 30 minutos de hidratação. Três ensaios biológicos foram realizados com ratos normais ou diabéticos, alimentados com dietas contendo diferentes concentrações de goma guar. No primeiro ensaio foram preparadas dietas contendo 0,2, 4, 6, 8 e 13% de goma guar e oferecidas a ratos normais por 30 dias. As dietas com 8 e 13% de goma guar foram mais eficientes na redução de colesterol, triacilgliceróis e LDL - colesterol, bem como na elevação da HDL - colesterol no soro sangüíneo (p<0,05). Nenhuma das dietas provocou alteração significativa da concentração de glicose sangüínea. As dietas contendo 8 e 13% de goma guar provocaram redução da ingestão alimentar e uma redução no ganho de peso corporal, embora o quociente de eficiência protéica operacional (PER.op) não tenha sofrido alteração. Um segundo ensaio foi realizado com ratos normais e dietas contendo 10 e 20% de goma guar ou celulose e com duração de 60 dias. Para a mesma concentração, a goma guar foi mais eficiente que a celulose em reduzir colesterol, triacilgliceróis e LDL - colesterol e, ao mesmo tempo, elevar o nível de HDL - colesterol. Observou-se que a goma guar, a 10 e 20% da dieta, elevou a relação HDL/LDL (3,94 e 3,80, respectivamente). A goma guar reduziu a glicose sangüínea durante o primeiro mês do ensaio, porém, no fim do segundo mês a concentração retomou ao nível inicial. O teste de tolerância à glicose mostrou uma redução da glicose sangüínea aos 30, 60 e 90 minutos após administração de 20 e 40 mg de goma guar por intubação orogástrica. As dietas com 10 e 20% de goma guar provocaram uma diminuição da ingestão alimentar e no ganho de peso corporal (p<0,05), em comparação com a dieta controle. Observou-se uma redução na absorção de energia (p<0,05) e um aumento no tempo de trânsito intestinal (retardo de 25%) nos animais que receberam dietas com goma guar. A goma guar causou um aumento de 19% no comprimento do intestino delgado e uma diminuição no peso fecal, em comparação à dieta sem goma guar. Realizou-se ainda um terceiro ensaio de 30 dias utilizando ratos diabéticos (diabetes mellitus) e dietas preparadas com O, 10 e 20% de goma guar. Apesar do fato de que o diabetes tivesse elevado à lipidemia em todos os animais, a goma guar fez baixar os níveis sangüíneos de colesterol, triacilgliceróis e LDL - colesterol, ao mesmo tempo em que elevou o nível de HDL - colesterol (p<0,05). Apesar do fato de que o teor de colesterol hepático dos ratos em goma guar não diferiu do da dieta controle, a absorção de gordura foi significativamente inferior nos ratos alimentados com goma guar. Resultado muito significativo foi a drástica redução nos níveis de glicose sangüínea dos ratos diabéticos em dietas com goma guar. A goma guar promoveu uma melhoria geral no estado dos ratos diabéticos em termos de ganho de peso corporal, elevação dos índices de absorção e utilização da proteína e redução da glicemia. Os resultados desta pesquisa mostram que a goma guar quando introduzida na dieta, em concentrações igualou superior a 10%, deverá ser efetiva no tratamento da hipercolesterolemia , diabetes e obesidade / Abstract: Guar gum derived from the endosperm of Cyamopsis tetragonoloba was used in this research and contained 75% soluble fiber, 7.6% insoluble fiber, 2.16% crude protein, 0,78% total lipids, 0.54% ash, and 9.55% moisture. Particle size (granulometry) and viscosity of the gum utilized during the assays, were evaluated. As to the size of particles, it was observed that 98.6% was smaller than 200 ?m. The viscosity was influenced by pH and time of hydration and the guar gum showed a viscosity 8 to 10 fold higher than pectin, soluble fiber utilized to comparation. Highest viscosity (3.64 Pa.s) was found to guar gum at pH 8.0 and 30 minutes hydration. Three biological assays were performed, using either normal or diabetic rats and different guar concentration in the diets. In the first assay diets were prepared containing O, 2, 4, 6, 8 and 13% guar gum, and normal rats were fed for 30 days. Diets with 8 and 13% guar gum were more efficient in reducing blood serum cholesterol, triacylglycerols and LDL cholesterol, but increased HDL - cholesterol (p<0.05). None of the diets caused significant alterations of the blood glucose level. Diets with 8 and 13% guar gum produced reduction of food intake and bodyweight gain although protein efficiency ratio (PER.op) was not changed. A second assay was performed using normal rats on diets containing 10 and 20% guar gum or cellulose and duration of 60 days. At the same concentration, guar gum was more effective than cellulose in reducing cholesterol, triacylglycerols and LDL - cholesterol, and at the same time increasing HDL - cholesterol. It was found that guar gum, at 10 and 20% in the diet, increased the HDL/LDL ratio (3.94 and 3.80, respectively). Guar gum decreased blood serum glucose during the first month of the experiment. At the end of the second month, however, glucose level returned to the initial level. Glucose tolerance test showed a significant reduction of blood glucose after 30, 60, and 90 min. of administration of 20 and 40mg of guar gum by oral-gastric intubation. Diets with 10 and 20% guar gum produced a reduction of food intake and a decrease in body weight gain (p<0.05), compared to the control diet. A decrease in energy absorption (p<0.05) and an increase in the intestinal transit (25% retardation) was observed with diets containing guar. Guar gum caused also a 10% increase in length of the small intestine and a decrease in fecal weight when compared to control and cellulose diets. A third assay was performed with 0, 10, and 20% guar gum with a duration of 30 days and using diabetic rats (diabete mellitus). In spite of the fact that diabetes elevated the lipidemia in all animals, guar gum decreased blood serum level of cholesterol, triacylglycerols and LDL-cholesterol, but increased HDL-cholesterol (p<0.05). Even though, liver cholesterol of rats fed guar diets did not differ from rats fed the control diet, fat absorption was significantly lower in the guar gum fed rats. The most significant result in this assay was the drastic reduction of blood glucose in rats treated with guar gum diet. The guar gum promoted a improvement of the diabetic rats in terms of body weight gain and the indexes of protein absorption and utilization. The results of this research showed that guar gum in the diet, at concentration equal or higher than 10%, should be effective in the treatment of hypercholesterolemia, diabetes and obesity / Doutorado / Doutor em Ciência da Nutrição