Variação no conteúdo de beta-glucanas em cultivares brasileiros de aveia

Portugués. Com o crescente interesse em alimentos funcionais e nutracêuticos, a aveia (Avena sativa L.) tem se destacado, devido ao seu teor de fibras alimentares e principalmente às beta-glucanas. As (1,3)(1,4)-beta-D-glucanas, fibras alimentares na maioria solúveis, atuam na redução do colesterol em indivíduos com hipercolesterolemia. Existem estudos para determinar as causas de variação do teor desta fibra em aveia, porém, pouco se sabe sobre a aveia cultivada no Brasil. O objetivo deste trabalho foi verificar se existem diferenças no conteúdo de beta-glucanas entre cultivares brasileiros e se há variação na porcentagem desta fibra devido ao ano de cultivo. Os cultivares IAC7, UFRGS14, UPF16 e UPF17 (3 amostras de cada), e ainda três amostras do cultivar IAC7 para cada ano de cultivo (97 e 98), foram analisados segundo os métodos da AACC (American Association of Cereal Chemists). Os teores médios (peso seco) de beta-glucanas foram 6,50% (IAC7), 4,30% (UFRGS14), 3,51% (UPF16) e 3,78% (UPF17), com erro padrão de ±0,084 e coeficiente de variação de 7,89 %. Observou-se efeito significativo dos cultivares (p=0,03) e grande variabilidade entre as amostras (p=0,0001). O cultivar IAC7 apresentou média de beta-glucanas de 5,11% em 97 e 6,50 % em 98 (erro padrão ±0,14; CV=10,53%) e observou-se efeito significativo do ano de cultivo.

Inglés. With the increasing interest in functional foods and nutraceuticals, oats (Avena sativa L.) have received special attention because of their dietary fiber contents, and specially of their beta-glucans. The mostly soluble dietary fibers (1,3)(1,4)-beta-D-glucans, reduce serum cholesterol in individuals with hypercholesterolemia. There are studies about the causes of variation in the contents of this fiber in oats, however, very little is known about Brazilian cultivars. The objective of this work was to verify if there were differences in the beta-glucan contents among brazilian cultivars and if there was variation in the percentage of this fiber due to the crop year. The cultivars IAC7, UFRGS14, UPF16 and UPF17 (3 samples each), and even three more samples of cultivar IAC7 for each year (97 and 98), were analyzed according to the AACC methods for beta-glucans. The mean content was 6.50% (IAC7), 4.30% (UFRGS14), 3.51% (UPF16) and 3.78% (UPF17), with standard error (S.E.) of ±0.084 and variation coefficient (C.V.) of 7.89%. A significant effect of the cultivars (p=0.03) and a great variability among the samples (p=0.0001) was observed. IAC7 had a mean beta-glucan content of 5.11% for 1997 and 6.50% for 1998 (S.E.±0.14; C.V.=10.53%) and a significant effect for the crop year was observed.