2024-03-28T23:26:26Z
https://ajfs.journals.ekb.eg/?_action=export&rf=summon&issue=3990
Alexandria Journal of Food Science and Technology
1687-3920
1687-3920
2008
5
1
Utilization of Some Vegetables and Fruits Waste As Natural Antioxidants
Natural antioxidants are in great demand today due to both consumer preference and health concerns associated with the use of synthetic antioxidants, so this study was carried out to investigate the extraction, identificationofantioxidant compounds in some vegetables and fruits waste and to evaluate its extract as natural antioxidants. Total phenolics were determined in methanolic extract. Phenolic compounds in each methanolic extract were screened by TLC and identifiedbyHPLC.AntioxidantactivitiesofthesewastematerialshavebeenmeasuredbyPV(PeroxideValue),CDH (Conjugated Diene Hydroperoxide), TBA (Thiobarbituric Acid Value), AV (Anisidine Value) and TV (Totox Value) methods. TLC plates showed that vegetables, and fruit waste, contained antioxidant components. The percentage of total phenolic content can be summarized as follows: olive leaves > tomato peel > orange peel > cucumber peel > water melon peel > potato peel. All extracts exhibited antioxidant activity. Tomato extract (600 ppm) has high antioxidant activity which was lower than the control sample and had the same activity as TBHQ (200 ppm) during storage period of sunfloweroil;thisextractalsoexhibitedantioxidantactivitywhichwashigherthancucumberpeeland water melon peel. From the economical point of view, vegetables and fruits waste as natural source of antioxidants may play an important role in industry.
natural antioxidant
health concerns
synthetic antioxidant
Phenolic compounds
conjugated diene hydroperoxide
TBHQ
2008
06
01
1
11
https://ajfs.journals.ekb.eg/article_20136_4b344e83ca33b08266deac4eddaadf59.pdf
Alexandria Journal of Food Science and Technology
1687-3920
1687-3920
2008
5
1
Effect of Pre-Treatments on the Quality of Dried Persimmon (Diospyros kaki) Fruit Sheets
The present study proposed to produce dried persimmon (Diospyros kaki) fruit sheets in order to determine whether it could be used as a substitute for fresh fruits. Chemical and physical properties of whole fresh persimmon fruits and pulps were investigated. The antioxidant activity, total tannin and crude fiberofwholepersimmonfruitwerehigher than that of the pulp. Meanwhile, total cartenoids, ascorbic acid and the contents of K, Ca, Mn and P were higher in pulp than in whole fruit. Both whole persimmon fruits and pulp were washed, crushed, purred and pre–treated with steaming, followed by immersion in 0.3% sodium metabisulfiteand0.2%citricacidsolutionsfor30minpriorto drying as a sheet form. Rehydration of dry sheets was completed in 5 min with moisture content of about 14%. The highest values of total soluble solids content and colour index were observed for persimmon pulp pre–treated with 0.3% sodium metabisulfite.Also,bothsamplesthatweretreatedwithsodiummetabisulfitehada goodrehydrationratio and received the highest average scores for the sensory evaluations (colour, taste, texture and odour).
Persimmon
DPPH
ESR free radical
Drying
vitamin c
minerals
Crude fiber
2008
06
01
13
22
https://ajfs.journals.ekb.eg/article_20137_7e66b09137a0384cefb1a031b0028390.pdf
Alexandria Journal of Food Science and Technology
1687-3920
1687-3920
2008
5
1
InfluenceofMilkTreatmentandAdjunctCulture on Quality of Ras Cheese
Classical techniques used to improve milk’s shelf life and safety are based on heat treatments, like pasteurization and sterilization. Those techniques modify some physic-chemical properties of milk, for example its coagulation by rennet. Microfiltrationconstitutesanalternativetoheattreatmenttoreducethepresenceofbacteriaandimprovethemicrobiological safety of dairy products without modifying the physic-chemical properties of milk. In this study, the effect of microfiltration(MF)andpasteurizationonproteolysis,lipolysisandflavordevelopmentinRascheeseduring 4 months of ripening were studied. Mixtures of adjunct cultures, isolated from artisanal dairy products, have been also evaluated in experimental Ras cheese for flavordevelopment.Inthefirsttrial,rawskimmilkwasmicrofilteredand then the protein/ fat ratio was standardized using pasteurized cream. The pasteurized milk with same protein/ fat ratio was also used in the second trial. Milk treatment “microfiltrationorpasteurization”affectinthecheesemakingprocedure for amount of added chymosin and cooking time. The chemical composition of cheeses seems to be affected by milk treatment “microfiltrationorpasteurization”ratherthantheculturetypes.Themoisturecontentwashigherand the pH was lower in pasteurized milk cheeses than in microfiltratedmilkcheesesatdayoneofmanufacture.Proteolysis and lipolysis during cheese ripening were lower in microfiltratedmilkcheesescomparingtopasteurizedmilk cheeses. Very significantvariationsinfreeaminoacids,freefattyacidsandsensoryevaluationhavebeenfoundamong the cultures used in Ras cheesemaking. In general, microfiltratedmilkcheesesreceivedhigherscoreinbody& texture and lower score in flavorcomparingwithpasteurizedmilkcheeses.
Ras cheese
microfiltration
pasteurization
proteolysis
2008
06
01
21
29
https://ajfs.journals.ekb.eg/article_20138_254fe0ac48cadd6192199c7ca1c27a4d.pdf
Alexandria Journal of Food Science and Technology
1687-3920
1687-3920
2008
5
1
Applications of Nanotechnology in the Food Industry: An Overview
Nanotechnology deals with the capability to image, measure, model, control and manipulate matter at dimensions of roughly 1–100 nanometer. The potential benefitsofnanotechnologyhavebeenrecognizedbymanyindustriesandcommercial products in many fieldsbasedonfundamentalandappliedresearchinphysics,chemistry,biology,engineering and material science. In contrast, applications of nanotechnology within the food industry are rather limited. However, achievements and discoveries in nanotechnology are beginning to impact the food industry and associated industries.This article provides an overview of some developmental efforts in the area of nanotechnology as it applies to food systems and industry. Such applications include the following: nanoemulsions, nanoparticles, nanolaminates, nanocomposites, nanofibers,nanoprecipitation,nanodispersion,nanocapsules.Furthermore,nanotechnologycanbeapplied to produce novel nutraceutical, functional foods and unique milk protein. Identificationofpathogensinfood,oil and fat industry, food packaging and Atomic Force Microscopy (AFM) as a nanotechnology tool in food science are all promising applications discussed in the present article.
nanolaminates
Nanocomposites
Nanofibers
nanotubes
Nanoparticles
Nanoprecipitation
liposomes
microemulsions
Nanoemulsions
Cubosomes
nanosensores
Nutraceuticals
Functional foods
oils & fats
pathogens
nanopackaging
milk protein
AFM
2008
06
01
31
42
https://ajfs.journals.ekb.eg/article_20139_76bc750bcd6b32d360a6c5f33e3eae75.pdf
Alexandria Journal of Food Science and Technology
1687-3920
1687-3920
2008
5
1
Chemical Composition and Occurrence of Mycotoxins in Six Blue-Mould-Ripened Cheeses in Egypt
Chemical composition (fat, moisture, protein, salt, titratable acidity, and pH), proteolysis (free amino acids), lipolysis (total volatile fatty acids and free fatty acids), and some mycotoxins were determined in all cheese samples studied. Saint Agur was characterised by its high concentrations of total protein (22.04%), total amino acids (5.21mg/g), fat (33.79%), and TVFA (25.3 ml NaOH/100 mg cheese) and lowest concentrations of salt (2.41%) and moisture (40.20٪). Bleu d’Auvergne, had a pH around 6.0, and the highest concentrations of salt in moisture (8.0%), soluble nitrogen (51.98%), moisture (47.09%) and salt (3.76%) of all cheeses investigated. Bleu d’Auvergne had the lowest fat content (28.42%) and TVFA (20.1 ml NaOH/100mg cheese) of all the cheeses studied.Cheese samples were analyzed for seven mycotoxins (Roqurfortine C, Mycophenolic acid, Penicillin acid, Aflatoxin G1, AflatoxinM1,AflatoxinB1,AflatoxinB2).RoqurfortineCwasdetectedin allof thebluemouldcheesesamples in concentrations of 1.6-14 μg kg-1. Two blue-cheese samples (Saint Agur and Moby blue) contained also 0.35 and 0.47 μg kg-1 mycophenolic acid, respectively. Penicillic acid was detected (0.12, 0.41 and 0.53-1 μg/ kg) in Gorgonzola, Saint Agur and Moby blue, respectively. AflatoxinG1,aflatoxinM1,aAflatoxinB1 andaflatoxinB2were not detected in the tested cheeses, this is likely to be due to best manufacturing practises applied in the cheese production, and at the same time the storage conditions are all strictly controlled in order to avoid mould contamination and aflatoxinsformation.
blue cheese
chemical properties
ripening indices
Aflatoxins
Mycotoxins
organolepticproperties
2008
06
01
43
50
https://ajfs.journals.ekb.eg/article_20140_888cfe09e35b4ce2185f1913ce092221.pdf
Alexandria Journal of Food Science and Technology
1687-3920
1687-3920
2008
5
1
Origin, History and Manufacturing Process of Egyptian Dairy Products: An Overview
The manufacturing process of the Egyptian dairy products was originated since the Pharonic period from 3200 to 332B.C. and was developed through the Greco-Roman period from 332 to 641 A.D., and then in the Arab Islamic period 641 A.D. until now. The manufacturing process of the Egyptian dairy products was very well developed, and modern automation took place in the large cities in both lower and upper Egyptian governotates. The manufacturing process of the traditional dairy products in the frontier governorates must be intensively and carefully investigated, because it has not been previously studied.The objective of the present article is to describe the origin, history and manufacturing process of the following Egyptian dairy products; Laban Rayeb, Laban Khad, Laban Zeer, Kishk, Laban Zabady, Labneh, Karish cheese, Mish cheese, Domiati cheese, Ras cheese, and Egyptian adopted plastic curd cheese varieties (Kashkaval, Provolone, Mozarella, Medaffarah and Halloumi), processed cheese, Ice cream and Al-Samn.
Egyptian dairy products
origin of dairy products
history of dairy products
processing of dairy products
Egyptian heritage
2008
06
01
51
62
https://ajfs.journals.ekb.eg/article_20141_83b69ba4dc88125b8cfaf9042790f13e.pdf