Ashraf Sharoba
Prof. Dr.Ashraf Sharoba, Professor of Food Technology , Faculty of Agriculture, Benha Univ. Egypt, since 1994. I have 30 years of teaching experience. I am supervised many undergraduate projects and many master and Ph.D. theses in Food Technology Department, Benha Univ. and other universities in Egypt. My filed is food engineering, food rheology, food texture and food technology. And I have the training expertise in my field, also I am scientific consultant to some food companies.
less
InterestsView All (14)
Uploads
Papers by Ashraf Sharoba
dairy products, and are found in a variety of environments. The aim of this study was to find out the ability of
bile salts and acid tolerance as well as antibacterial properties of the three lactobacillus strains namely
Lactobacillus acidophilus ATCC 20552, Lactobacillus casei DSM 20011 and Lactobacillus plantarum ATCC
14917. The acid tolerance test was studied under pH 2.0 and 3.0 with 6.5 as a control. The cell count for the acid
tolerance test was obtained at an interval of 0, 1, 2 and 3 hours, and was pour plated on Man Rogosa, and Sharpe
(MRS) agar to be incubated at 37 °C for 24 hours. All cells were selected for bile tolerance test in MRS broth
containing bile concentrations of 0 % as control and 0.1, 0.3, 0.5 and 0.7 % as test and antibiotic susceptibility.
Results showed that the three strains of Lactobacilli have ability to tolerate acid and bile salts and resistance to
0.4 % of phenol and were susceptible for streptomycin (10 μg), ampicilline (10 μg), chloramphenicol (30 μg),
erytromycin (15 μg), amoxicillin/clavulanic acid (30 μg) and rifampicin (5 μg). All strains have antimicrobial
activity against seven indicator bacteria included Bacillus cereus DSM 351, Escherichia coli ATCC 25922,
Staphylococcus aureus ATCC 12600, Listeria monocytogenes, Salmonella typhimurium ATCC14028,
Klebseilla pneumonia ATCC 1705 and Pseudomonas aeruginosa ATCC 43495.
proportion of essential amino acids (38.81% of the protein) and a source of naturally rich in vitamins especially
vitamin B complex such as vitamin B 12 (193 μg / 100 g) and folic acid (9.66 mg / 100 g), which helps the
growth and nutrition of the child brain, also rich in calcium and iron it containing (1043.62 and 338.76 mg / 100
g, respectively) to protect against osteoporosis and blood diseases as well as a high percentage of natural fibers.
So, the spirulina is useful and necessary for the growth of infants and very suitable for children, especially in the
growth phase, the elderly and the visually appetite. It also, helps a lot in cases of general weakness, anemia and
chronic constipation. Spirulina contain an selenium element (0.0488 mg/100 g) and many of the phytopigments
such as chlorophyll and phycocyanin (1.472% and 14.18%), and those seen as a powerful antioxidant. It ensures
the whole food and alkaline balance of the body. The spirulina used in the production of snack food by some
addition percentages zero, 2.5, 5, 7.5, 10 and 12.5%. Data of sensory evaluation results showed that the adding
spirulina by ratio 12.5% had lower score for most properties compared to other tested. The chemical analysis
was done, the obtained data showed that the add spirulina a large role in increasing protein ratio and ash where
the results were (9.43 - 18.11%) and (1.31 - 2.67%) for the samples the control sample and 10% spirulina. The
physical properties measurement were done, such as density, the expansion rate, grain index, WSI and WAI, the
results showed that the adding rate of spirulina was improvmant the physical properties of the snacks. It was
safety study microbiology samples prepared by adding snack spirulina and all samples were microbiologically
safe. Rheological properties were measured for snacks samples by using (Instron universal testing machine
model 4301) for measuring textures, all texture parameters were improved and increased constants textures add
spirulina and was at the same time economical cost and therefore can be produced for domestic use as well as
can be exported abroad.
progressively increasing in Egypt. Amaranth plant grows rapidly, with a high tolerance to
arid conditions and poor soils. So, a trial was made to use whole amaranth meal in
producing sausage. The quality attributes of sausage produced from beef meat as main
ingredients or substituted by different levels of whole amaranth meal were studied.
Chemical composition, freshness tests, physicochemical evaluation, microbiological
examinations were determined. The energy values for produced sausage were estimated.
Texture properties were measured using the food texture Instron Universal Testing
Machine (Model 4302) (Penetration test (PT) and Compression test (CT). Sensory
evaluation for produced sausage was carried out and the data were statistically analyzed.
Obtained results showed that using of whole amaranth meal increased total carbohydrate
and ash but the other chemical composition were decreased in sausage. While there are
changing in chemical composition, the nutritional values for all produced sausage were
nearly the same. The TVN and TBA were increased with increasing storage time. The
increase in TVN and TBA of substituted samples were lesser than control sample. In the
same time TVN and TBA for all produce sausage samples were within the Egyptian
standard requirements. Whole amaranth meal increased cooking yield and decreased
frying and cooking loss. The microbiological quality of all produced sausage was within
the Egyptian standard requirements. The sausage substituted with 5, 10 % of whole
amaranth meal were accepted nearly as control sausage. Texture properties of sausage are
affected by substitute levels of whole amaranth meal and storage period. The results
indicated that whole amaranth meal can be utilized in making sausage.
different blends of red pepper paste (100% tomato paste as control, 50% tomato + 50%
red pepper, 40% tomato + 60% red pepper, 30% tomato + 70% red pepper, 20% tomato
+ 80% red pepper, 10% tomato + 90% red pepper, 100% red pepper and 90% tomato +
10% dry red pepper). Two methods were used for preparing red pepper paste (open pan
and vacuum technique). The red pepper paste was sensory evaluated. Data obtained for
sensory evaluation indicated that red pepper paste produced with the vacuum technique
more acceptable than traditional technique (open pan). The paste prepared with open pan
technique had low score in color, taste, odor and overall all acceptability. The red pepper
paste prepared by vacuum technique was stored for 9 months gradually chemically
analyzed, examined for microbiological quality and represented for sensory evaluation.
Data indicated that paste prepared from 50% tomato and 50% red peppers was better than
other paste products in sensory properties. Total soluble solids were slightly decreased
during storage period. Chemical analysis indicated that pH values and total sugars were
decreased with increasing storage time for paste products. The β-carotene, lycopene and
ascorbic acid were increased with increasing the percentage of adding red pepper in the
blendes. These components were decreased with increasing storage time of paste product.
Up to six and nine months the microbiological quality of tomato paste was changed. The
changing in the microbiological quality was under food low allowance. Sensory
evaluation indicated that there are significant differences in all properties of paste
samples during storage period.
marjoram (Origanum marjorana ) were screened for their possible antioxidant and antimicrobial properties as
well as their chemical compositions. According to gas chromatography (GC/ MS) were identified, 39, 16 and 54
compounds of essential oils lemongrass, thyme and marjoram, respectively. The major constituents were 9-cisretinal
, δ-2-carene and isomethyl-α-ionol for lemongrass; carvacrol, 2,5-dihydroxybenzoic acid and α –pinene
for thyme and 9-cis-retinal, t-butylhydroquinone and p-mentha-3,8-diene for marjoram. The major phenolic
and flavonoid compounds of ethanolic extracts identified using HPLC were benzoic , coumarin , hisperidin and
hispertins for lemongrass; salicylic ,ellagic , hisperidin and rosmarinic for thyme and benzoic, pyrogalol, ,
hisperidin and narerigin for marjoram. Antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl
(DPPH) free radical scavenging. Results showed the superior of ethanolic extracts (low IC50) at lower
concentrations than essential oils for scavenged DPPH. The antimicrobial activity (by disc diffusion tests) of
different plant essential oils and extracts against 11 strains of microorganisms was done. The essential oils of the
tested plants have a stronger antimicrobial activity than those of ethanolic extracts which did not exhibit
antimicrobial activity against some microbial strains.
dairy products, and are found in a variety of environments. The aim of this study was to find out the ability of
bile salts and acid tolerance as well as antibacterial properties of the three lactobacillus strains namely
Lactobacillus acidophilus ATCC 20552, Lactobacillus casei DSM 20011 and Lactobacillus plantarum ATCC
14917. The acid tolerance test was studied under pH 2.0 and 3.0 with 6.5 as a control. The cell count for the acid
tolerance test was obtained at an interval of 0, 1, 2 and 3 hours, and was pour plated on Man Rogosa, and Sharpe
(MRS) agar to be incubated at 37 °C for 24 hours. All cells were selected for bile tolerance test in MRS broth
containing bile concentrations of 0 % as control and 0.1, 0.3, 0.5 and 0.7 % as test and antibiotic susceptibility.
Results showed that the three strains of Lactobacilli have ability to tolerate acid and bile salts and resistance to
0.4 % of phenol and were susceptible for streptomycin (10 µg), ampicilline (10 µg), chloramphenicol (30 µg),
erytromycin (15 µg), amoxicillin/clavulanic acid (30 µg) and rifampicin (5 μg). All strains have antimicrobial
activity against seven indicator bacteria included Bacillus cereus DSM 351, Escherichia coli ATCC 25922,
Staphylococcus aureus ATCC 12600, Listeria monocytogenes, Salmonella typhimurium ATCC14028,
Klebseilla pneumonia ATCC 1705 and Pseudomonas aeruginosa ATCC 43495.
sweeteners (aspartame and stevioside) were evaluated using a rotational viscometer at concentrations of (0.5% and
1.2g/L for hydrocolloids and sweeteners, respectively), Hydrocolloids and sweeteners concentrations were selected
depending on preliminary sensory evaluation. The rheological properties for nectar samples were measured at
four temperatures (5, 25, 50 and 75°C). The flow behavior of the nectars was characterized as non-Newtonian
(pseudoplastic with yield stress). The pseudoplasticity increased due to hydrocolloids addition, while it decreased
due to sweeteners addition. Herschel-Bulkley and Bingham rheological models were used to describe the flow
behavior of papaya–apricot nectars samples. Addition of aspartame and stevioside reduced the viscosity of nectar
samples compared to control nectar samples. Nectar sample contains hydrocolloids had a higher and best sensory
and rheological characteristic. Papaya-apricot nectar containing guar gum, xanthan gum or arabic gum had high
score in overall all acceptability.
range 0.0 to 100 s-1 and Oscillatory tests were studied at a wide range of
temperatures (0 - 50 °C) using a Physica UDS 200 rheometer. The results
indicated that the apricot puree behave as non-Newtonian fluids (pseudoplastic)
and have a definite yield stress. The relationship between (ηeff) and temperature
of apricot puree was examined. High correlation was found between (ηeff) and
temperature. The ηeff decrease with increase in temperature. Oscillatory test data
revealed weak gel-like (dispersion structure) behavior of the apricot puree:
magnitudes of G´ were higher than those of G´´, and both increased with
Oscillatory frequencies. The effect of temperature on their viscosity can be
described by means of an Arrhenius-type equation. The flow activation energy
for viscous flow depends on the chemical composition. Chemical and physical
tests for apricot puree were made. On the other hand, the mechanical properties
for apricot fruits were studied by using Instron Universal Testing Machine
model 4301. The effects of storage at different temperatures on physicomechanical
properties were studied by using the flat plate compression test and
penetration test. Maximum force (N) and elastic modulus values (MPa)
decreased with increasing storage time. Maximum force, Young’s modulus and
energy for apricot fruit were decreased in the non chilled condition and with
increasing storage time.
treatment to extend product shelf life and reduce risk of pathogens. Antimicrobial
activities of pullulan films incorporated silver nanoparticles (Ag NPs) 100 nm, zinc
oxide nanoparticles (ZnO NPs) 110 nm, oregano oil (OR) 2% and rosemary oil (RO)
2%, against Listeria monocytogenes and Staphylococcus aureus, were evaluated
during the preparation and storage at 4, 25, 37, and 55°C up to 49 days in plate
overlay assays (in vitro). Moreover, the prior pullulan films were applied directly on
turkey deli meat were inoculated by L.monocytogenes and S. aureus and stored at 4
°C for two weeks. The results from this study demonstrate that Ag NPs and OR edible
films more active than ZnO NPs and RO, respectively. The optimum conditions for
storage pullulan edible films incorporated nanoparticles (NPs) and/or essential oils
(EOs) were 4 and 25°C. Ag NPs, ZnO NPs, OR, and RO based films were exhibited
significant effects as antibacterial activity against pathogens. These results revealed
that (NPs) and/or (EOs) have a good potential to be incorporated into pullulan to make
an antimicrobial edible film or coating for various food applications.
(GPP) by-products from food industry, as a starting raw material to produce dietary fiber powders and the feasibility
of producing cakes intended for people suffering from obesity or over weight and diabetes. The physicochemical
properties of dietary fiber powder were first evaluated. The results showed that the fiber contents, compositions and
hydration properties (water and oil holding capacity and swelling capacity) of the fiber powder. Some food
processing by-products {(OW), (CP), (PP) and (GPP)}, is a rich sources of fibres. The OW, CP, PP and GPP byproducts
were replaced with wheat flour (72%) at 5, 10, 15 and 20% levels and studied for rheological characteristics.
Water absorption increased significantly with increasing by-products from 0 to 20%. Dough stability and dough
development were increased. Resistance to extension values significantly increased, whereas extensibility values
decreased. The produced fiber substituted cakes achieved a reduction in calories. Cakes were prepared from blends of
wheat flour (72%) with 5, 10, 15 and 20% fruits and vegetables by-products. The volume of cakes decreased with
increase in fruits and vegetables by-products content from 0 to 20%. Cakes prepared from 20% of by-products OW,
CP, PP and GPP had a higher ratio of dietary fibres. Sensory evaluation showed that all high fiber substituted cake
samples were significantly lower than control cake sample in all sensory characteristics, except cake samples
prepared with 5 and 10% of orange waste and carrot pomace had no significant differences (P>0.05) with control
cake. However, there were significant differences between cake samples containing the same type of fiber source at
5, 10, 15 and 20% replacement levels. The highest and lowest scores in the same type of fiber source for all attributes
were that achieved by cake samples with fiber source at 5 and 20% replacement levels, respectively. Texture
properties of cake were affected by replacement levels of fiber source. The results indicated that OW, CP, PP and
GPP by-products can serve as a good source of dietary fibres.
microbiological safety of foods. The aim of this study was to evaluate the effectiveness of pullulan films containing essential
oils and nanoparticles against 4 foodborne pathogens. Initial experiments using plate overlay assays demonstrated that 2%
oregano essential oil was active against Staphylococcus aureus and Salmonella Typhimurium, whereas Listeria monocytogenes
and Escherichia coli O157:H7 were not inhibited. Two percent rosemary essential oil was active against S. aureus, L.
monocytogenes, E. coli O157:H7, and S. Typhimurium, when compared with 1%. Zinc oxide nanoparticles at 110 nm
were active against S. aureus, L. monocytogenes, E. coli O157:H7, and S. Typhimurium, when compared with 100 or 130
nm. Conversely, 100 nm silver (Ag) nanoparticles were more active against S. aureus than L. monocytogenes. Using the
results from these experiments, the compounds exhibiting the greatest activity were incorporated into pullulan films and
found to inhibit all or some of the 4 pathogens in plate overlay assays. In challenge studies, pullulan films containing the
compounds effectively inhibited the pathogens associated with vacuum packaged meat and poultry products stored at
4 °C for up to 3 wk, as compared to control films. Additionally, the structure and cross-section of the films were evaluated
using electron microscopy. The results from this study demonstrate that edible films made from pullulan and incorporated
with essential oils or nanoparticles may improve the safety of refrigerated, fresh or further processed meat and poultry
products.
free of hazardous contaminants. However, previous investigations showed that wheat could be contaminated by
aflatoxins above the limits that may be critical for health. In this study, use of the high oxidising power of ozone achieved
degradation of aflatoxin B1. Samples were subjected to ozonation at various ozone concentrations (20, 40ppm) and
exposure time (5, 10, 15, 20 min). The reduction percentages of aflatoxin B1 in artificially contaminated wheat 10 μg/kg
were 84.1 and 86.75% after exposures to 20 and 40 ppm ozone for 20min respectively, and 86.7 and 96.66 % with 20
μg/kg after exposures 20 and 40 ppm ozone for 20 min, respectively. The percentage of inhibition zone from Aspergillus
flavus was 46.4 % to 87.8 % after ozonation using concentration 20 ppm for 5 and 20 min respectively. While with 40
ppm ozone inhibition zone was 65.6% and 95.6 % with 5 and 20 min respectively. Exposure of strain to 20 ppm ozone
inhibition of product of AFB1 percentage of 40.94%, 52.5%, 59.32% and 60.4 % for exposure time 5, 10, 15 and 20 min,
respectively. However, observed increase on inhibition of AFB1 with topping up ozone dose to 40 ppm attained 55.2%,
64%, 74.5% and 77.2% with 5, 10, 15 and 20 min exposure time respectively.
of sunflower oil (SO), cottonseed oil (CO) and
palm olein (PO) during deep frying for 4–16 h were
investigated. In the different oils, linoleic acid decreased
while palmitic, stearic and oleic acids increased in the bath
oil during frying. Total phenolic content (TPC) in different
oils increased during frying and strongly correlated with
frying time. As frying progressed, it was observed that the
rate of increase in TPC was relatively slower in PO than in
the SO and CO. The shear stress versus shear rate results
was fitted to Newtonian, Bingham and Herschel–Bulkley
rheological models. The flow behaviour of fresh and fried
SO, CO and PO was recorded at 25 C. Fresh oils showed
Newtonian behaviour with correlation coefficients greater
than 0.99 at 25 C and slight non-Newtonian behaviour
after frying. Palm olein showed higher increase in viscosity
in comparison to CO and SO. Rheological parameters of
vegetables oils showed great changes, wherein the highest
change in viscosity was recorded after 16 h of frying. Palm
olein had higher flow behavior parameters than SO and
CO. The increase in frying time caused an increase in K,
gB, s0HB, s0B, and g values, while the n values decreased
with increasing the frying time. The viscosities of oils were
plotted against the levels of C18:1 and C18:2 wherein
highly positive correlations were found between them
(R2 = 0.99). The temperature dependence of viscosity was
studied by using the Arrhenius relationship and the
activation energy indicates the sensitivity of viscosity to
changes in temperature. It could be concluded that the
rheological parameters can provide an overall estimate of
oil quality during frying.
and after lyophlization process and found that the lyophlization process improved the efficiency of the enzymes
and active ingredients as a result of low moisture to 5%. The use of bee venom and royal jelly improved the
therapeutic efficiency of some diseases: improving the sexual efficiency, the functions of the kidney and
decrease the rate of glucose by using the doses of 500 mg and 1 gram of (1mg of lyophilized bee venom
+500mg of lyophilized royal jelly +25mg honey) / kg of body weight orally daily for adult male rats for a
month. This study showed that the treatment of adult male rats by 1 gram (1mg of lyophilized bee venom
+500mg of lyophilized royal jelly +25mg honey) / kg of body weight orally alone resulted in increasing the
weights of the testis and the body of the epididymus, sperm count, testosterone hormone, the percentage of live
sperm, and glutathione level, accompanied with decrease in malondialdehyde level and the percentage of sperm
abnormality. The oral administration of (1mg of lyophilized bee venom +500mg of lyophilized royal jelly
+25mg honey) in doses of 500 mg and 1 g/kg body weight today for one month increased urea concentration in
serum and decreased in urine, urea clearance in urine was also decreased as compared to control group. (1mg of
lyophilized bee venom +500mg of lyophilized royal jelly +25mg honey) in a dose of 1 g/kg body weight daily
decreased serum, urine and creatinine levels. Decrease in serum glucose level was also observed when the test
animals were treated with (1mg of lyophilized bee venom +500mg of lyophilized royal jelly +25mg honey) in a
dose of 500mg and 1g /kg body weight daily. Remarkable for one month was showed increasing in body weight
of adult rats that treated with 1g (1mg of lyophilized bee venom +500mg of lyophilized royal jelly +25mg
honey) /kg of body weight compared with control group. This study recommended that using mixtures of
lyophilized bee venom and royal jelly which are dissolved in honey as therapy of sexual efficiency, kidney and
sugar diseases.