Efeito do processamento e da estocagem sobre a formação de óxidos de colesterol em ovos

Author(s)

Sandra Emi Kitahara

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2004-10-27

Examining board members

Alfredo Tenuta Filho; Luiz Antonio Gioielli; Jorge Mancini Filho; Carmen Cecilia Tadini; Elizabeth Aparecida Ferraz da Silva Torres

• Advisor: Alfredo Tenuta Filho

Abstract

The cholesterol is an important sterol of the human body. It is a component of the cellular membranes, therefore being found in all tissues. It is the forerunner of several compounds vital to the organism, as biliar salts and steroid hormones. The importance of cholesterol in our organisms is, therefore unquestionable. This compound could be synthetized by the human tissues or acquired from the diet, being widely distributed in foods of animal origin. Egg, butter and some sea foods are examples of foods with high concentrations of cholesterol. As an unsaturated lipid, cholesterol is susceptible to oxidation, forming compounds known as cholesterol oxides. Presence of oxygen, light and temperature are some of the pre-conditioning factors for cholesterol oxidation. The concern in relation to these products formed by the oxidation of cholesterol is growing, because several works show a biological activity associated to the development of diseases, as coronarian disease and cancer. The egg is a food rich in nutrients and very versatile, consumed so much on its natural form, as on its processed form, being pasteurization and desidratation by atomization the main utilized processes. The storage of these products through their shelf lives could lead to the cholesterol oxides formation. Considering the pre-conditioning factors and the raising worry related to the cholesterol oxides, the present work had as objective identify and quantify these compounds in a food of great nutritional importance and largely consumed in Brazil and in the world. Therefore, fresh and processed eggs and egg yolks were analyzed during each shelf life. In relation to the process, the spray-drying and the freeze drying had influence on cholesterol oxides formation, quantified with a HPLC. The spray drying, as well as the spray drying had influence on oxidation stability, availed as TBARS concentration form. In relation to the storage during the shelf life, no significant difference was noticed. (AU)