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Master's Dissertation
DOI
10.11606/D.11.2005.tde-26042005-141101
Document
Author
Full name
Aelson Aloir Santana Brum
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 2004
Supervisor
Committee
Arce, Marisa Aparecida Bismara Regitano D (President)
Ferrari, Roseli Aparecida
Oetterer, Marilia
Title in Portuguese
Métodos de extração e qualidade da fração lipídica.
Keywords in Portuguese
aveia
frango
lipídios – extração
qualidade dos alimentos
Abstract in Portuguese
Um estudo crítico foi realizado utilizando quatro métodos clássicos de extração de lipídios em aveia em flocos e peito de frango. Foram comparados os rendimentos, o tempo de extração, a repetibilidade de cada método e a qualidade oxidativa da fração lipídica obtida. As metodologias utilizadas foram as de Soxhlet, com n-hexano como solvente, nos períodos de quatro e oito horas de extração; Folch et al., com clorofórmio e metanol na proporção de 2:1 (v/v); Bligh & Dyer, com clorofórmio, metanol e água na proporção de 1:2:0,8 (v/v) e Hara & Radin, com n-hexano e isopropanol, na proporção de 3:2 (v/v). Os resultados obtidos indicaram que para a aveia em flocos, os métodos de Soxhlet e Bligh & Dyer apresentaram um rendimento superior (7,71 % e 7,66 %, respectivamente) em relação ao método de Hara & Radin e Folch et al. (6,61 % e 6,93 %, respectivamente). No estudo do peito de frango, os métodos de Soxhlet, Folch et al. e Bligh & Dyer apresentaram um rendimento satisfatório de lipídios totais, sendo, respectivamente, de 1,56 %, 1,56 % e 1,65 %. Apesar do bom rendimento em lipídios totais, o método de Soxhlet afetou a qualidade da fração lipídica em ambas amostras, demonstrada pela presença de peróxidos (4,39 e 4,19 meq O2/kg no peito de frango; 3,71 e 3,70 meq O2/kg na aveia em flocos) e pela acidez oléica (2,58 % de ácidos graxos livres (AGL) no peito de frango; 2,25 e 2,24 % AGL na aveia em flocos), em ambos os períodos de tempo da extração. Com base nos resultados deste trabalho, indica-se a metodologia de Bligh & Dyer para os casos em que haja interesse em uso posterior das frações lipídicas, em detrimento da de Soxhlet, não recomendável para o fim mencionado.
Title in English
Extraction methods and quality of the lipid fraction.
Keywords in English
chicken
food quality
lipid extraction
oat
Abstract in English
A critical study was carried through with four clasical methods of extraction of lipids from chicken breast and oat flakes. The yield, the extraction time, the repeatability of each method and the oxidative quality of the lipid fraction were evaluated and compared. The methodologies evaluated were Soxhlet, with n-hexane as the solvent, in periods of four and eight hours of extraction; Folch et al., with chloroform and methanol in the ratio of 2:1 (v/v); Bligh & Dyer, with chloroform, water and methanol, in the ratio of 1:2:0.8 (v/v), and Hara & Radin, with n-hexane and isopropanol, in the ratio of 3:2 (v/v). The results indicated that for oat flakes, the methods Soxhlet and Bligh & Dyer presented higher yields in total lipids (7.71 % and 7.66 %, respectively) than the methods Hara & Radin and Folch et al. (6.61 % and 6.93 %, respectively). In the study with chicken breast, the methods Soxhlet, Folch et al. and Bligh & Dyer presented the highest yields, being respectively 1.56 %, 1.56 % and 1.65 %.Despite the good yields in total lipids, the Soxhlet method affected the quality of the lipid fraction in both samples, demonstrated by the presence of peroxides (4.39 and 4.19 meq O2/kg in chicken breast; 3.71 and 3.70 meq O2/kg in oat flakes) and by the acid values (2.58 % FFA [free fatty acids] in chicken breast for both extractions; 2.25 and 2.24 % FFA in oat flakes,) for both periods of time evaluated. Based on the results obtained in this research, the authors recommend Bligh & Dyer methodology whenever there is interest in further use of the lipid fraction and strongly disencourage Soxhlet method for the purpose mentioned.
 
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Publishing Date
2005-04-28
 
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