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Ionizing radiation effects of Cobalt-60 on the physical-chemical, sensorial and microbiological of bread with addition of linseed (Linum usitatissimum)

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Author(s):
Neila Camargo de Moura
Total Authors: 1
Document type: Doctoral Thesis
Press: Piracicaba.
Institution: Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB)
Defense date:
Examining board members:
Solange Guidolin Canniatti Brazaca; Maria Elisabeth Machado Pinto e Silva; Miriam Coelho de Souza; Marta Helena Fillet Spoto
Advisor: Solange Guidolin Canniatti Brazaca
Abstract

The incorporation of functional ingredients on breading products has grown very much lately, because of the preoccupation with the consumers\' health. The linseed has awakened the interest by its high level of fiber, lignin, omega-3 and antioxidants compounds. The objective of the present work is evaluate the ionizing radiation effect of 60Co on the physical-chemical, sensorial and microbiological characteristics of bread with addition of different concentration of brown linseed. There were elaborated 3 types of bread: French roll, form bread prepared with the mixture and form bread produced with conventional ingredients. It was added smashed brown linseed on the bread dough, with concentrations of 8% and 12%. After the preparation, the three kinds of bread packed with polypropylene packages and taken to the IPEN/USP (Institute of Nuclear Energetic Research/University of São Paulo) and irradiated with doses of 6, 8 and 10 kGy. Treatments were elaborated without the addition of linseed and without irradiation, for control, totalizing 12 distinct treatments, to each bread formula tested. Chemical analyses were made (centesimal composition, anti-nutritional compounds, anti-oxidant activity, glycemic index, fat acids, complex B vitamins and minerals); physical analyses (cooking index, volume, color and water activity); sensorial analyses (preference tests and Descriptive Quantitative Analysis - ADQ); microbiological analysis and a survey about irradiated products. It could be seen that the addition of linseed was efficient to increase the level of alimentary fiber and the level of lipids on the 3 bread formula. The three kinds of bread that received the linseed addition and that were not irradiated presented increase on the level of total phenolic; however, when the samples which received the linseed addition were submitted to the irradiation process, it could be noticed the decrease of the antioxidant capacity. There was an increase on the level of omega-3, depending on the percentage of linseed added to the bread. The linseed addition was effective to raise the level of potassium, phosphorus and magnesium. But, the irradiation decrease the level of vitamin B1 and vitamin B6 of the three kinds of bread. The irradiation did not influence the quality of the obtained bread. The sample tasters, not trained, accepted the bread independently of the doses of applied radiation. The ADQ test evidenced that the sensorial characteristics of the samples depend on the ingredient variation used on the formulas and on the radiation. The irradiated samples presented mold counting considerably lower than the non-irradiated samples, which increased the shelf-life of those products. The survey reveals that the majority of the people interviewed has little or any knowledge about radiation and believe that the irradiation can generate some kind of harm for human beings. Therefore, the bread production enriched with mashed linseed and submitted to gamma radiation is promising, given that the chemical and sensorial properties were considered satisfactory, besides the increasing of the shelf-time (AU)

FAPESP's process: 08/05616-1 - Effects of ionized radiation from Co60 in physical-chemical and sensory characteristics of bread added with flaxseed (Linum usitatissimum)
Grantee:Neila Camargo de Moura
Support Opportunities: Scholarships in Brazil - Doctorate