Thesis (M.Sc.)-Cairo University, 2023.

Bibliography: pages 181-201.

The aim of this study is to investigate the chemical components of cinnamon, rosemary and clove volatile
oils by GC/Mass as well as the antioxidant and antimicrobial activity of these oils and their mixture
(1:1:1, v:v:v) to select the best volatile oil or mixture and also the best concentration for preparing beef
sausage. The effect of different exposure times to laser radiation (Helium-Neon laser wavelength at 632.8
nm) was also studied to select the best one for preparing and preserving of beef sausage. Results indicated
that 23, 10, and 18 compounds were identified from cinnamon, rosemary, and clove which represented
97.26, 98.50 and 98.80 %, respectively. Cinnamaldehyde, 1, 8 Cineole, and Eugenol were the most
abundant chemical compounds in cinnamon, rosemary, and clove volatile, respectively. Volatile oils
mixture had higher antioxidant and antimicrobial activity than each volatile oil individually and could be
arranged in descending order according to their antioxidant and antimicrobial potency as follows: volatile
oil mixture ˃ cinnamon ˃ clove ˃ rosemary volatile oil. Based on antioxidant and antimicrobial results, it
could be recommended to use a volatile oils mixture (cinnamon, clove and rosemary, 1:1:1, v: v: v) in the
preparation of beef sausage. Also, results indicated that, 500 ppm of volatile oil mixture was the best
concentration in preparation of beef sausage due to improve sensory properties when compared with other
concentrations, and 18 minutes (9 min for each side) was the best exposure time to laser radiation for
sausage because there weren't any recorded negative changes in physiochemical properties of the product.
Also in this study, the effect of best concentration of volatile oils mixture (500 ppm) and best exposure
time of laser radiation (18 min) on quality attributes and shelf life of beef sausage during cold storage was
investigated. Lipid oxidation (peroxide value, thiobarbituric acid, and acid value), pH value and total
volatile nitrogen (TVN) of sausage treatments were not affected significantly by laser radiation or volatile
oils mixture immediately after processing (at zero time) but affected (p<0.5) during cold storage. Sausage
prepared with 500 ppm volatile oils mixture and exposed to laser irradiation (T3) had significantly lower
lipid oxidation, pH and TVN than other sausage treatments at any time of cold storage. Moreover,
microbial load (total bacteria count, psychrophilic bacteria, coliform group, lipolytic and proteolytic
bacteria, Salmonella spp., Staphylococcus aureus and yeast and mold counts) of beef sausage decreased
by exposure to laser radiation for 18 minutes (T1) and by adding the volatile oil mixture at 500 ppm (T2)
as well as volatile oils mixture and laser radiation combination (T3) when compared with control sample.
Therefore, the treatment of beef sausage with volatile oil mixture and laser radiation combination led to
improve chemical, physical and sensory properties and more effective in reduction of microbial load and
extending the shelf life of beef sausage to 20 days at 4±1ºC compared with sausage treated with volatile
oils mixture only (15 days), sausage treated with laser rays only (10 days) and control sample (5 days).

الهدف دراسة تاثير الزيوت الطيارة واشعة الليزر علي جودة وفترة صلاحية السجق البقري اثناء التخزين بالتبريد و التعرف علي المركبات الكيميائية للزيوت الطيارة القرفة وإكليل الجبل والقرنفل بالإضافة إلى النشاط المضاد للأكسدة ومضادات الميكروبات لهذه الزيوت و اختيار أفضل تركيز لمخلوط الزيوت وقت للتعرض لإشعة الليزر (هيليوم-نيون ليزر عند طول موجي 632.8 لتحضير وحفظ سجق اللحم البقري . و من اهم الناتئج ان مخلوط الزيوت المختبرة كانت أعلى في قدرتها كمضادات للأكسدة والمضاد للميكروبات من كل زيت متطاير على حدة. أدى علاج سجق اللحم البقري بمزيج مخلوط الزيوت العطرية و إشعة الليزر إلى تحسين الخصائص الكيميائية والفيزيائية والحسية وزيادة فعالية تقليل الحمل الميكروبي وزيادة فترة صلاحية السجق اللحم البقري أثناء التخزين بالتبريد إلى 20 يومًا في 4 ± 1 درجة مئوية بمقارنة للسجق المعامل بمخلوط الزيوت الطيارة فقط (15 يومًا)، و السجق المعالج بأشعة الليزر فقط (10 أيام) وعينة الكنترول (5 أيام).

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