الفهرس 
Chapter 1: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Fruits and vegetables are important crops with a critical role in the diet and a very high daily consumption all over the world due to their functional and nutritional value as they are the main sources of fibers, vitamins, minerals, phenolic compounds including flavonoids, phytoestrogens, sulfur compounds, monoterpenes, and bioactive peptides.
The consumption of minimally processed fruits and vegetables including ready-to-eat or ready-to-use has increased worldwide in the last decade due to its convenience, freshness, and improved quality. The commercialization of minimally processed fruits and vegetables is limited to rapid degradation and short shelf life due to tissue damage and microbial growth because of the processing.
The shelf life extension of minimally processed fruits and vegetables is achieved by various techniques that aimed to inhibit microbial growth and chemical undesirable reactions which affect their quality and safety. Synthetic antimicrobials and antioxidants are widely used in food products, consumers are concern about their potential toxicological effects. Therefore, the demand for natural alternatives including plant extracts was increased as natural additives with antioxidant, antibacterial, and antifungal activities. These activities relied on the plant phytochemicals which are biologically active compounds that have a significant role in health maintenance and food preservation.
Therefore, the present study aimed to extend the shelf life, enhance the safety, and quality of minimally processed fruits and vegetables using natural plant extracts. This aim was achieved by collecting the leaves of guava, moringa, olive, and pomegranate peels then dry them, the dried leaves and peels were extracted with three solvents namely water, ethanol (70%), and methanol (70%). The extracts were evaluated for their phenolic, flavonoid contents, antioxidant, and antimicrobial activity by calculating the total phenolic, total flavonoid content, DPPH radical scavenging activity, agar well diffusion, and the MIC were determined. Also, apples and carrots were brought, stored, graded, washed with tap water, peeled, cut; undesirable parts were removed, sprayed with different concentrations of the antimicrobial solutions, packaged in low-density polyethylene bags, and stored in a refrigerator at 5±1º c. Furthermore, the impact of selected extracts on the shelf life and quality attributes was assessed through microbiological (determination of the total psychrotrophic bacterial, fungal, and Enterobacteriaceae group count), chemical (determination of the moisture content, PH, total titratable acidity, and total soluble solids), and sensorial analysis (color, odor, texture, taste, and overall acceptability) to choose the appropriate extract and concentration that can be used as a natural preservative.