Ahmed M. Hamed

Dr. Ahmed M. Hamed

Dairy Science, Cairo University, Giza, Al Jīzah, Egypt
orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 August 2020 in Foods
Verified
Journal Article
Open access
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FDFaten Dhawi
Faten Dhawi
Hossam S. El-BeltagiHossam S. El-Beltagi
Hossam S. El-Beltagi
EAEsmat Aly
Esmat Aly
AHAhmed M. Hamed
Ahmed M. Hamed
Recently, there is an increasing demand for functional yoghurts by consumer, especially those produced through the incorporation of food of plant origin or its bioactive components. The current research was devoted to formulating functional buffalo yoghurt through the addition of 0.1 and 0.2% of fenugreek (Trigonella foenum-graecum) seed flour (F1 and F2) and Moringa oleifera seed flour (M1 and M2). The effects of fortification were evaluated on physicochemical, total phenolic content (TPC), antioxidant activity (AOA), the viability of yoghurt starter, and sensory acceptability of yoghurts during cold storage. Moringa oleifera seed flour had higher contents of TPC (140.12 mg GAE/g) and AOA (31.30%) as compared to fenugreek seed flour (47.4 mg GAE/g and 19.1%, respectively). Values of TPC and AOA significantly increased in fortified yoghurts, and M2 treatment had the highest values of TPC (31.61, 27.29, and 25.69 mg GAE/g) and AOA (89.32, 83.5, and 80.35%) at 1, 7, and 14 days of storage, respectively. M2 showed significantly higher antibacterial activity against E. coli, S. aureus, L. monocytogenes, and Salmonella spp. and the zones of inhibition were 12.65, 13.14, 17.23 and 14.49 mm, respectively. On the other hand, control yoghurt showed the lowest antibacterial activity and the zones of inhibition were (4.12, 5.21, 8.55, and 8.39 mm against E. coli, S. aureus, L. monocytogenes, and Salmonella spp., respectively). Incorporation of 0.1% and 0.2% of moringa seed flour (M1 and M2) led to a higher content of Ca, P, K, and Fe and lower content of Mg and Zn as compared to F1 and F2, respectively. Thus, it could be concluded that fenugreek and Moringa oleifera seed flour can be exploited in the preparation of functional novel yoghurt.


26 July 2018 in Analytical Letters
Verified
Journal Article
Closed access
AHAhmed M. Hamed
Ahmed M. Hamed
MIMahmoud Ibrahim
Mahmoud Ibrahim
LGLaura Gámiz Gracia
Laura Gámiz Gracia
AGAna M. García-Campaña
Ana M. García-Campaña
NANatalia Arroyo-Manzanares
Natalia Arroyo-Manzanares
The consumption of plant-based milk has increased due to their nutritional attributes. However, these products may contain aflatoxins if contaminated raw materials were used, although little concern is present in international regulation regarding this topic. In this work, dispersive liquid–liquid microextraction (DLLME) was used for the determination of the most important aflatoxins (B1, B2, G1, and G2) in oat, rice, coconut, almond, and birdseed plant-based milk and milk-based products enriched with oats, almonds, and walnuts using high-performance liquid chromatography (HPLC) with photochemical derivatization and fluorescence detection. Calibrations in matrix were performed for all of the samples, obtaining satisfactory linearity, with correlation coefficients exceeding 0.994 for all of the aflatoxins. The precision in terms of repeatability and intermediate precision, expressed as the relative standard deviation, was lower than 9.7%, and recoveries ranged between 82 and 104%, fulfilling current legislation for the determination of aflatoxins. In addition, the limits of quantification were 0.5 µg L−1 for the aflatoxins, allowing the determination of these compounds below the maximum levels established by European Commission in these commodities. Finally, 23 commercial products were analyzed to characterize the presence of these toxins.

8 December 2011 in Food Additives & Contaminants: Part B
Verified
Journal Article
Closed access
ESElham M. El Sayed
Elham M. El Sayed
AHAhmed M. Hamed
Ahmed M. Hamed
SBSanna M. Badran
Sanna M. Badran
AMAmr A. Mostafa
Amr A. Mostafa
The aim of this paper was to assess the content of selected essential metals (Fe, Zn, Cu and Cr) and some heavy metals (Pb and Cd) in raw cow's milk collected from different Egyptian areas during different periods of one year (January–February, May–June and September–October 2009). Twenty-one samples of raw milk were analysed using inductively coupled plasma–atomic emission spectrometry for quantitative determination. The highest metal accumulation levels for Cd, Cr, Fe and Cu are found in milk samples collected from Shubra, while samples from Menofia and Tanash are high in Pb and Zn, respectively. On the other hand, the highest metal accumulation levels were during January–February for Cd, Cr and Zn. In the period of May–June, the content of Pb, Cu and Fe were the highest, while the samples during the September–October period are characterised by the lowest metal content.

19 July 2016 in Food Analytical Methods
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Journal Article
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AHAhmed M. Hamed
Ahmed M. Hamed
DMDavid Moreno-González
David Moreno-González
AGAna M. García-Campaña
Ana M. García-Campaña
LGLaura Gámiz Gracia
Laura Gámiz Gracia

24 August 2020 in Foods
Verified
Journal Article
Open access
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MIMahmoud Ibrahim
Mahmoud Ibrahim
ZHZizhen Huang
Zizhen Huang
TSTakuya Suzuki
Takuya Suzuki
TEToshiki Enomoto
Toshiki Enomoto
AHAhmed M. Hamed
Ahmed M. Hamed
EREhab Romeih
Ehab Romeih
Rubus suavissimus S. Lee leaves, also known as Chinese sweet tea or Tiancha, are used in folk medicine in southern China. This study evaluated the impact of the addition of Chinese sweet tea extract (0.25%, 0.5%, and 1%) on the chemical composition, organoleptic properties, yogurt culture viability, and biological activities (i.e., antioxidant, anticancer, and antihypertensive activities) of yogurt. Seven phenolic compounds were reported in Chinese sweet tea for the first time. The numbers of the yogurt culture were similar across all yogurt treatments. The yogurt supernatant with 0.25%, 0.5%, and 1% Chinese sweet tea extract had a total phenolic content that was 3.6-, 6.1-, and 11.2-fold higher, respectively, than that of the control yogurt. The biological activities were significantly increased by the addition of Chinese sweet tea extract: Yogurt with the addition of 1% Chinese sweet tea extract had the highest biological activities in terms of the antioxidant activity (92.43%), antihypertensive activity (82.03%), and inhibition of the Caco-2 cell line (67.46%). Yogurt with the addition of 0.5% Chinese sweet tea extract received the highest aroma and overall acceptability scores. Overall, Chinese sweet tea extract is a promising food ingredient for producing functional yogurt products that may substantially contribute to reducing the risk of developing chronic diseases such as cancer and cardiovascular disease.