Orientador : Valdemiro C. Sgarbieri / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e Agricola / Made available in DSpace on 2018-07-16T22:21:26Z (GMT). No. of bitstreams: 1 Schonhaus_Ilana_M.pdf: 4737812 bytes, checksum: 0e94ed6df55a96bdc74d47d31d2d7ced (MD5) Previous issue date: 1980 / Resumo: Os principais objetivos deste trabalho foram concentrados no estudo comparativo químico e nutricional de quatro variedades de milho em dois estágios de maturação: verde (20 dias após polinização) e seco. As quatro variedades estudadas são caracterizadas pelos seguintes genótipos de endosperma para carboidratose proteínas: Maya Normal (Su02); Doce Piramex (su02); Maya (Su02) e Nutrimaiz ou Doce-Opaco (su02). O estudo químico envolveu determinações da composição centesimal, variação no teor dos principais componentes estruturais, extração fracionada das protelnas, composlção em aminoácidos das frações protéicas e da farinha interal. Os resultados indicaram que ocorreram modificações profundas na composição do grão com o amadurecimento e que as diferenças entre variedades são condicionadas pelos respectivos genótipos. Em relação à composição centesimal observou-se nas quatro variedades consideráveis variações com a maturação. As porcentagens de nitrogênio não protéico, de fibra e de cinza diminuíram, enquanto, que o teor de lípide aumentou nas quatro variedades. Os milhos Doce Piramex e Nutrimaiz apresentaram 8.0 e 5.3% de lípide, respectivamente, no estágio seco, contra 5.0 e 6.0 para as variedades Maya Normal e Maya Opaco. A extração fracionada das proteínas revelou um comportamento similar entre as variedades cujos genótipos dos endospermas são semelhantes para proteinas, ou seja, entre o Maya Normal e o Doce Piramex (02) e entre o Maya Opaco e o Nutrimaiz (°2>, Todas as variedades apresentaram maior teor de proteínas 4 salino-solúveis (albuminas mais globulinas) no estágio verde, em maior concentração no Nutrimaiz e no Maya Opaco, sendo que estas diminuíram com o amadurecimento. As variações registradas foram: 58,2 a 16,0; 56,1 a 21,0; 60,7 a 40,1 e 69,8 a 49,6% pa ra as variedades Maya Normal, Doce Piramex, Maya Opaco e NutrimaiZ, respectlvamente. Por outro lado, a fração zelna variou de 16,4 a 40,0% e de 14,9 a 37,2% no Maya normal e no Doce Piramex, nos dois estágios de maturação, em comparação com o Maya Opaco 8,0 a 10,8% e o Nutrimaiz, 5,1 a 6,0%. O Maya Opaco e o Nutrimaiz apresentaram, no estágio seco, 25,8 e 29,8% de glutelina 3, respectivamente, em contraste com 14% no Maya Normal e 18% no Doce Piramex. Cada fração protéica revelou uma composição característica, sendo que as frações albumina, globulina e glutelina 3 apresentaram melhor perfil aminoacídico. Assim, as farinhas das variedades Nutrimaiz e Maya Opaco apresentaram uma composição mais favorável que as demais, nos dois estágios de maturação. As principais deficiências encontradas na composição das proteínas dos milhos Maya Normal e Doce Piramex referem-se aos aminoá cidos essenciais lisina (2,4 e 2,7%, respectivamente) e triptofano, 0,4%. Para o Maya Opaco e para o Nutrimaiz. A concentração de lisina na proteína foi de 4,6% e para o triptofano 1,2 e 0,9%. A relação leucina/isoleucina, no estágio seco, é também muito alta no Maya Normal e no Doce Piramex contribuindo para as qualidades nutricionais inferiores dessas variedades em relação ao Maya Opaco e ao Nutrimaiz. A avaliação nutricional foi feita pela determinação de PER e de balanço de nltrogenlo. Os valores de PER caíram com a maturação de 1,9 para 1,2 no Maya Normal e de 2,0 para 1,4 no 5 Doce Piramex, enquanto que permaneceu praticamente constante, em torno de 2,6, no Maya Opaco e no Nutrimaiz. Esses valores de verao ser comparados com 2,9 para a dieta de caseína. O valor biológico caiu de 70%, no estágio verde, para 50,8 e 55% no estágio seco, no Maya Normal e Doce Piramex, respectivamente. Para o Nutrimaiz e para o Maya Opaco o valor biológico permaneceu constante em torno de 74%. Em relação à capacidade de promover crescimento em ratos, estudos estatísticos demonstraram que não houve diferença significativa entre as variedades Maya Opaco e Nutrimaiz em relação ao padrão caseína, enquanto as variedades Doce Piramex e Maya Normal apresentaram diferença significativa a nível de 5% no estágio verde e 1% no estágio seco em relação ao padrão. Assim, concluímos que as variedades Nutrimaiz e Maya Opaco são nutricionalmente superiores ao Maya Normal e ao Doce Piramex nos dois estágios de maturação, sendo que o duplo-mutante Nutrimaiz herdou as características favoráveis dos genes paternos, constituindo-se numa variedade que apresenta uma composição protéica mais favorável, além de conter açúcares de melhor qualidade e maior teor de óleo. Estas características conferem ao Nutrimaiz propriedades nutricionais iguais ou superiores ao Maya Opaco, oferecendo uma alternativa favorável em relação a um maior consumo de milho'"in natura" ou processado / Abstract: The principal aim of the present work was a comparative chemical and nutritional study of 'four varieties of 'corn in two stages of maturation: green (20 days after polli nation) and dry. The four varieties studied are characterized by the following endosperm genotypes with respect to carbohydrates and protein: Normal Maya (Su02); Sweet Piramex (suo2); Opaque Maya (Su02) and Nutrimaiz or Sweet-Opaque (su02). The chemical investigat~on involved determinations of percentual composition, variation in the content of the main structural components, amino acid composition of the protein fractions and of .the whole flour. The results indicated that there are a marked modification of the grain composition during maturation and that the differences between the varieties are conditioned by the respective genotypes. Considerable variations were observed in the percentual compositions of the four varieties. Non protein nitrogen, ash, and fiber decreased with maturation whereas the lipid content increased. The Sweet Piramex and Nutrimaiz showed 8.0 and 9.3% of lipid, respectively, in the dry stage of maturation, against 5.0 and 6.4 for the Normal Maya and Opaque Maya. Fractional extraction of proteins disclosed a similar behaviour of varieties with respect to endosperm genotypes,that is, a similarity exists between Normal Mãya and Sweet Piramex (02) and between 'Opaque Maya and Nutrimaiz (02) regarding variation of the contents of different protein fractions, during the maturation processo All varieties showed a greater content of saline-soluble proteins (albumins and globulins) in the green stage their concentration being greate in Nutrimaiz and Opaque Maya, but diminishipg with maturation. The variations observed were: 58.2 to 16.0; 56.1 to 21.0; 60.7 to 40.land 69.8 to 49.6% in the varieties Normal Maya, Sweet Piramex, Opaque Maya and Nutrimaiz, respectively. O the other hand, the zein fraction varied from 16.4 to 40.0% and from 14.9 to 37.2% in Normal Maya and Sweet Piramex for green and dry stages of maturation, compared with 8.0 to 10.8% for Opaque Maya and 5.1 to 6.0% for Nutrimaiz Opaque Maya and Nutrimaiz contained in the dry stage 25.8 and 29.8% of glutelin 3, where as Normal Maya and Sweet Piramex contained 14.0 and 18.0%, respectively. Each protein fraction had a characteristic composition; the albumin, globulin and glutelin 3 presenting a better amino acid pattern. Thus Nutrimaiã and Opaque Maya floursshowed a more favourable composition in any maturing stage than the remaining varieties. The main deficiencies found in the composition of Normal Maya and Sweet Piramex are related to the essencial amino acids lysine (2.4 and 2.7%) and triptophan (0.4 and 0.4%, respectively) whereas in both Opaque Maya and Nutri maiz lysine accounted for 4.6% and triptophan for 1.2 and 0.9%. The leucine/isoleucine ratio is much higher in the Maya Normal 5.3) and Sweet Piramex (4.7) as compared with that of Opaque Maya (3.3) and Nutrimaiz (3.2) which results in lower nutritional quality for the first two varieties. Nutritional evaluation was done by PER and nitrogen balance determinations. The PER dropped on maturation frem 1.9 to 1.2 for the Maya Normal and 2.0 to 1.4 for the Sweet Piramex whereas it remained practically constant, around 2.6, for the Maya Opaque and Nutrimaiz. These values shall be compared with 2.9 for the casein diet. The biological value drepped frem 70%, in the green stage, to 50.8 and 55% in the mature (dry) stage for the Maya Normal and Sweet Piramex, respectively. For Nutrimaiz and Maya Opaque the biological value remained essentially constant areund 74%. Regarding the growth promoting capacity in rats, statistic studies showed that there was no signigicant difference between the varieties Opaque Maya and Nutrimaiz compared with casein, whereas Sweet Piramex and Normal Maya showed, in relation to casein, significant differenceat 5% leveI in the green stage and at 1% leveI in the dry stage. This leads to the conclusion that the Nutrimaiz and Maya Opaque were superior to the Normal Maya and Sweet Piramex in both stage of maturation. Thl'! rk.l1'1)l p m..+;""+ Mtiizirited the favourable characteristics of the paternal genes, which confers on it a better chemical composition than that of the ancestral varieties, thus, originating a variety of more favourable protein composition. It contains, in addition, sugars of better quality and a higher percentage of oil. These characteristics ensure to Nutrimaiz nutritional properties equalor superior to those of Maya Opaque, offering prospects of a greater consumption of com in its natural or processed formo / Mestrado / Ciência de Alimentos / Mestre em Ciência de Alimentos

Thesis (M. A. Agriculture (Agricultural Economics)) -- University of Limpopo, 2021 / Maize seeds differ according to varieties.The traditional maize varieties(also referred to as (Landraces)are maize varieties that have been cultivated and subjected to selection by farmers for generations.They retain a distinct identity and lack formal crop improvement. Improved maize varieties,on the other hand,are bred with characteristics such as drought and disease tolerance. This research was conducted to determine the attributes preferred by farmers when making a maize varietal choice.To be specific, the study aimed to achieve the following objectives:(i) Identify and describe socio economic characteristics of smallholder maize farmers’ in Mogalakwena Municipality; (ii) Analyse socioeconomic characteristics of smallholder maize farmers in Mogalakwena Municipality; (iii) Identify different maize varieties grown by smallholder farmers in Mogalakwena Municipality,and (iv) determine and analyse factors influencing farmers’choice ofa maize variety. Descriptive statistics and the Multinomial Logistic Regression Model were used for data analysis.The results of the study revealed that 64% of the respondents had formal education.This meant that they have the capability to grasp more information, if provided with trainings. It was found that 75% of the farmers did not have access to extension service which is supposed to play a significant role in agricultural information dissemination.The most grown maize variety was land race varieties which constituted 59.5%. This percentage was said to be resultant from limited access to the seed market. Infact,80% of the farmers had to travel an average of 42 kilomteres to access the market which also had a limited number of varieties.The Multinomial Logistic Regression Model revealed that only 5 variables (Educational level, farm size, yield, extension contact and knowledge of maize varieties )were significantat1%,5%,1%,1% and1%, respectively.The majority of farmers were old people with little access to extension service and an inadequate farming knowledge which lead to a highper centage of farmers continuing to grow landrace varieties. Based on the findings, this study recommend further research on attributes that influence farmers varietal choice and Government intervention in provision for resources and development of existing and new infracstrcture to encourage extension service delivery. Keywords:Landrace,improvemaizevariety,smallholderfarmer

Thesis (M. A. Agricultural Science (Agricultural Economics)) -- University of Limpopo, 2021 / Maize seeds differ according to varieties. The traditional maize varieties(also referred to as (Landraces)are maize varieties that have been cultivated and subjected to selection by farmers for generations. They retain a distinct identity and lack formal crop improvement. Improved maize varieties, on the other hand, are bred with characteristics such as drought and disease tolerance. This research was conducted to determine the attributes preferred by farmers when making a maize varietal choice. To be specific, the study aimed to achieve the following objectives:(i) Identify and describe socio economic characteristics of smallholder maizefarmers’ in Mogalakwena Municipality;(ii) Analyse socioeconomic characteristics of smallholder maize farmers in Mogalakwena Municipality;(iii)Identify different maize varieties grown by smallholder farmers in Mogalakwena Municipality, and (iv) determine and analyse factors influencing farmers’ choice of a maize variety. Descriptive statistics and the Multinomial Logistic Regression Mode lwere used for data analysis. The results of the study revealed that 64% of the respondents had formal education. This meant that they have the capability to grasp more information, if provided witht rainings. It was found that 75% of the farmers did not have access to extension service which is supposed to play a significant role in agricultural information dissemination. The most grown maize variety was landrace varieties which constituted 59.5%. This percentage was said to be resultant from limited access to the seed market. Infact, 80% of the farmers had to travel an average o f42 kilomteres to access the market which also had a limited number of varieties. The Multinomial Logistic Regression Model revealed that only 5variables (Educational level, farm size, yield, extension contact and knowledge of maize varieties) were significant at 1%, 5%,1 %,1% and1%, respectively. The majority of farmers were old people with little access to extension service andaninad equate farming knowledge which lead to a high percentage of farmers continuing to grow landrace varieties. Based on thef indings, this study recommend further research on attributes that influence farmers varietal choice and Government intervention in provision for resources and development of existing and new infracstrcture to encourage extension service delivery Keywords: Landrace, improve maize variety, smallholder farmer