ReviewPomegranate peel and peel extracts: Chemistry and food features
Introduction
Pomegranate (Punica granatum L.) is better known in some countries as the fruit of Eden (Al-Quran) for its pleasant taste and excellent health benefiting properties. Over the last decade, pomegranate fruit and fruit extracts have been shown to possess preventive and attenuating activities against numerous chronic and health/life threatening maladies such as cancer (Lansky and Newman, 2007, Orgil et al., 2014), type 2 diabetes (Banihani, Swedan, & Alguraan, 2013), atherosclerosis and cardiovascular diseases (Al-Jarallah et al., 2013, Aviram et al., 2008, Hamoud et al., 2014, Rosenblat et al., 2006, Sestili et al., 2007). Interestingly, the above nutraceutical properties are not limited to the edible part of pomegranate fruit: in fact the non-edible fractions of fruit and tree (i.e. peel, seeds, flowers, bark, buds and leaves), although considered as waste, contain even higher amounts of specific nutritionally valuable and biologically active components as compared to the edible fruit (Orgil et al., 2014, Rosenblat et al., 2006, Sestili et al., 2007). Indeed, PoP and PoPx, hold significant free radical scavenging, anti-microbial, antiatherogenic and antimutagenic properties and are reported to produce ameliorating effects against many critical maladies (Aviram et al., 2008, Malviya et al., 2013, Sestili et al., 2007, Zahin et al., 2010). Unfortunately, functional foods containing PoP or PoPx are not, in general, well accepted by consumers because of their relatively reduced sensory features (Akpinar-Bayizit et al., 2012, Ismail et al., 2014, Sharma et al., 2014, Syed et al., 2013).
Nonetheless, the above health promoting features prompt the food entrepreneurs to focus on PoP and PoPx-containing food preparations including food supplements, nutraceuticals and phenolics enriched diets (Ismail et al., 2012, Kanatt et al., 2010, Naveena et al., 2008b, Qu et al., 2012). In addition to their nutraceutical relevance, PoP and PoPx exhibit important technical functions (antioxidant, antimicrobial, colourant and flavouring) and may also act as excellent natural additives for food preservation and quality enhancement. As a consequence, on account of these whole properties the use of peel’s fractionated compounds in food and nutraceutical industry is on the rise (Ismail et al., 2012, Kanatt et al., 2010, Naveena et al., 2008b, Qu et al., 2012). In particular, since the peel fraction of pomegranate is a valuable reservoir of diversified polyphenols such as sugar-free mono and oligomeric ellagitannins, it has been frequently utilized as natural antioxidant in various dietary supplements. Currently, to minimise the problem of its bad taste, commercial formulations of PoPx dietary supplements are available as capsules, tablets, and soft gels.
Apart from the established inclusion of PoP in several ayurvedic therapies and the recent tendency to an increased utilisation, the food use of PoP and PoPx is still poor and underestimated (Ismail et al., 2012, Ismail et al., 2014). The aim of the present review is to highlight the importance of PoP, PoPx and their biological fractions as food bulking agents and/or valuable substitutes of common synthetic food additives, providing baseline information on their potential applications with regard to the general issues of food safety, preservation, enrichment and quality enhancement.
Section snippets
Pomegranate peel phytochemistry
PoP – which accounts for about 50% of fruit weight is characterised by the presence of high molecular weight phenolics, ellagitannins, proanthocyanidins, complex polysaccharides, flavonoids and appreciable quantities of microelements that, on the whole, exhibit strong anti-mutagenic, antioxidant, antimicrobial and apoptotic properties (Dikmen et al., 2011, Li et al., 2006, Prakash et al., 2013, Ricci et al., 2006, Tezcan et al., 2009). The fruit contains a rich variety of flavonoids,
Structure activity relationship of PoP phenolics
Ellagitannins are commonly referred to as metabolites of gallotannins. As briefly discussed above, this unique group of phenolics is easily hydrolysable. Hydrolysis releases hexahydroxydiphenic acid that spontaneously lactonizes to form ellagic acid, a relatively stable monomeric structure of high antioxidant potential (Aguilera-Carbo et al., 2008, Kaponen et al., 2007).
PoP and the mesocarp of the fruit contain high concentration of hydrolysable tannins i.e. 27–172 and 32–263 g/kg respectively,
PoPx extraction optimisation and extracts stability
Ethanol, water and their mixtures – although exhibiting decreased ability to yield antioxidants as compared to methanol – are of course considered as the food grade solvents for commercial extraction of plant phenolics. Optimisation of extraction conditions to yield the maximum level of food grade antioxidant phenolics involves: the type of solvent (ethanol or water) or solvent ratio, the particle size of the plant material, the solvent-solid ratio, extraction temperature and time. Ultrasonic
PoP and PoPx – a natural class of food additives
Today it is generally accepted that functional foods from plant origin provide a clinically documented health benefit for the prevention, management or treatment of chronic diseases, particularly cardiovascular maladies and cancer. Since pomegranate is one of the most popular functional foods, consumption and marketing of its juice has been rapidly expanding worldwide. Moreover, the utilisation of pomegranate juice or juice derivatives as food colourants and flavour enhancers (Al-Maiman &
Functional and toxicological levels of PoP and PoPx
Alike any other plant extract, PoPx might in principle generate toxicity if the consumption or exposure levels exceed threshold limits. Since the utilisation of PoP and its extracts in food products for nutraceutical and functional purposes is on the rise, the toxicological/safety issue deserves the highest consideration. Lethal doses or concentrations of PoPx and of some fractionated constituent have been studied in vitro and in vivo in the past few years. The pioneer study by Vidal et al.
Conclusions
A plethora of literature highlights the ethnopharmacological and nutraceutical features of PoP and PoPx confirming their potential to act as health ameliorating biological ingredients. Relatively fewer reports deal with their possible toxicology, dietary ranges and consumption patterns. Some studies report the ingestion of pomegranate and its peel fractions in the form of pills, capsules and gels as conventional treatment regimens against certain diseases in countries of the developing world.
Acknowledgements
This work is a part of the Ph.D. studies of Tariq Ismail, Lecturer Department of Food Science and Technology, Bahauddin Zakariya University, Multan-Pakistan. The authors are grateful to higher education commission of Pakistan for funding various projects to investigate into various fruits and vegetable wastes and their potential for food use.
References (99)
- et al.
The effect of pomegranate extract on coronary artery atherosclerosis in SR-BI/APOE double knockout mice
Atherosclerosis
(2013) - et al.
Changes in physical and chemical properties during pomegranate (Punica granatum L.) fruit maturation
Food Chemistry
(2002) - et al.
Thermal characteristics of a water soluble extract obtained from pomegranate skin: Developing a state diagram for determining stability
Industrial Crops and Products
(2013) Antimicrobial activity of pomegranate (Punica granatum L.) fruit peels
International Journal of Food Microbiology
(2009)Hydrolyzable tannin analysis in food
Food Chemistry
(2012)- et al.
Structure-activity relationships for antioxidant activities of a series of flavonoids in a liposomal system
Free Radical Biology and Medicine
(1998) - et al.
Pomegranate and type 2 diabetes
Nutrition Research
(2013) - et al.
Seasonal and cultivar variations in antioxidant and sensory quality of pomegranate (Punica granatum L.) fruit
Journal of Food Composition and Analysis
(2009) - et al.
Pomegranate peel phenolics: Microencapsulation, storage stability and potential ingredient for functional food development
LWT-Food Science and Technology
(2014) - et al.
Identification and quantification of phenolic compounds from pomegranate (Punica granatum L.) peel, mesocarp, aril and differently produced juices by HPLC-DAD–ESI/MSn
Food Chemistry
(2011)
Pomegranate extract (POMx) decreases the atherogenicity of serum and of human monocyte-derived macrophages (HMDM) in simvastatin-treated hypercholesterolemic patients: A double-blinded, placebo-controlled, randomized, prospective pilot study
Atherosclerosis
Inhibition of Listeria monocytogenes by pomegranate (Punica granatum) peel extract in meat pate at different temperatures
Food Control
Flavonoid antioxidants: Chemistry, metabolism and structure-activity relationships flavonoid antioxidants: Chemistry, metabolism and structure-activity relationships
Journal of Nutritional Biochemistry
Efficiency of pomegranate peel extracts in stabilization of sunflower oil under accelerated conditions
Food Research International
Pomegranate peel and fruit extracts: A review of potential anti-inflammatory and anti-infective effects
Journal of Ethnopharmacology
A galactomannan polysaccharide from Punica granatum imparts in vitro and in vivo anticancer activity
Carbohydrate Polymers
Correlation between saliva protein composition and some T-I parameters of astringency
Food Quality and Preference
Punica granatum (pomegranate) and its potential for prevention and treatment of inflammation and cancer
Journal of Ethnopharmacology
Anti-inflammatory effects of Punica granatum Linne in vitro and in vivo
Food Chemistry
Evaluation of antioxidant properties of pomegranate peel extract in comparison with pomegranate pulp extract
Food Chemistry
Comparative efficacy of pomegranate juice, pomegranate rind powder extract and BHT as antioxidants in cooked chicken patties
Meat Science
The antioxidative and anti-proliferative potential of non-edible organs of the pomegranate fruit and tree
LWT-Food Science and Technology
Safety assessment of pomegranate fruit extract: Acute and subchronic toxicity studies
Food and Chemical Toxicology
Extraction modeling and activities of antioxidants from pomegranate marc
Journal of Food Engineering
Biological control of tomato bacterial speck using Punica granatum fruit peel extract
Crop Protection
Effects of flavonoids on nonenzymatic lipid peroxidation: Structure–activity relationship
Biochemical Medicine and Metabolic Biology
Antioxidant activity of Punica granatum fruits
Fitoterapia
Cytoprotective effect of preparations from various parts of Punica granatum L. fruits in oxidatively injured mammalian cells in comparison with their antioxidant capacity in cell free systems
Pharmacological Research
Optimization of ultrasonic-assisted extraction of pomegranate (Punica granatum L.) peel antioxidants by response surface methodology
Separation and Purification Technology
Antioxidant activity and total phenolic, organic acid, and sugar content in commercial pomegranate juices
Food Chemistry
Quality and antioxidant properties of a reduced-sugar pomegranate juice jelly with an aqueous extract of pomegranate peels
Food chemistry
Studies on the toxicity of Punica granatum L. (Punicaceae) whole fruit extracts
Journal of Ethnopharmacology
Chemical, physico-chemical and functional properties of pomegranate (Punica granatum L.) bagasses powder co-product
Journal of Food Engineering
Broad spectrum antimutagenic activity of antioxidant active fraction of Punica granatum L. peel extracts
Mutation Research
Microbial production of ellagic acid and biodegradation of ellagitannins
Applied Microbiology and Biotechnology
Fruit based natural antioxidants in meat and meat products: A review
Critical Reviews in Food Science and Nutrition
The therapeutic potential of pomegranate and its products for prevention of cancer
Chemical composition, water sorption isotherm, and phenolic contents in fresh and dried pomegranate peels
Drying Technology
Antioxidant capacity versus chemical safety of wheat bread enriched with pomegranate peel powder
Food and Function
Palatability and chemical safety of apple juice fortified with pomegranate peel extract
Food & Function
Pomegranate phenolics from the peels, arils, and flowers are antiatherogenic: Studies in vivo in atherosclerotic apolipoprotein E-deficient (E0) mice and in vitro in cultured macrophages and lipoproteins
Journal of Agricultural and Food Chemistry
Acute and subacute toxicity study of the ethanol extracts of Punica granatum (Linn). Whole fruit and seeds and synthetic ellagic acid in swiss albino mice
Asian Journal of Pharmaceutical Clinical Research
The effect of pomegranate (Punica granatum L.) byproducts and ellagitannins on the growth of human gut bacteria
Journal of Agricultural Food Chemistry
Antioxidant and antiradical activities of flavonoids
Journal of Agricultural and Food Chemistry
Enrichment of functional properties of ice cream with pomegranate by-products
Journal of Food Science
A study on the anticonvulsant and antianxiety activity of ethanolic extract of Punica granatum Linn
International Journal of Pharmacy and Pharmaceutical Sciences
Investigation of nutrient content, phytochemical content, antioxidant activity and antibacterial activity of inedible portion of pomegranate (Punica granatum L.)
European Journal of Medicinal Plants
Effect of vacuum packaging and pomegranate peel extract on quality aspects of ground goat meat and nuggets
Journal of Food Science and Technology
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