Opinion on the Hurdles and Potential Health Benefits in Value-Added Use of Plant Food Processing By-Products As Sources of Pheno
Total Page：16
File Type：pdf, Size：1020Kb
International Journal of Molecular Sciences Review Opinion on the Hurdles and Potential Health Benefits in Value-Added Use of Plant Food Processing By-Products as Sources of Phenolic Compounds Adriano Costa de Camargo 1,2,3,4,*, Andrés R. Schwember 1, Roberto Parada 1, Sandra Garcia 2 , Mário Roberto Maróstica Júnior 5, Marcelo Franchin 6, Marisa Aparecida Bismara Regitano-d’Arce 3 and Fereidoon Shahidi 4,* 1 Departamento de Ciencias Vegetales, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Casilla 306-22, Santiago, Chile; [email protected] (A.R.S.); [email protected] (R.P.) 2 Department of Food Science and Technology, Londrina State University, Londrina 86051-990, Parana State, Brazil; [email protected] 3 Department of Agri-Food Industry, Food & Nutrition, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba 13418-900, São Paulo State, Brazil; [email protected] 4 Department of Biochemistry, Memorial University of Newfoundland, St. John’s, NL A1B 3X9, Canada 5 Department of Food and Nutrition, University of Campinas—UNICAMP, Campinas 13083-862, São Paulo State, Brazil; [email protected] 6 Department of Physiological Sciences, Piracicaba Dental School, University of Campinas, Piracicaba 13414-903, São Paulo State, Brazil; [email protected] * Correspondence: [email protected] (A.C.d.C.); [email protected] (F.S.); Tel.: +1-709-864-8552 (F.S.) Received: 1 October 2018; Accepted: 31 October 2018; Published: 6 November 2018 Abstract: Plant foods, their products and processing by-products are well recognized as important sources of phenolic compounds. Recent studies in this field have demonstrated that food processing by-products are often richer sources of bioactive compounds as compared with their original feedstock. However, their final application as a source of nutraceuticals and bioactives requires addressing certain hurdles and challenges. This review discusses recent knowledge advances in the use of plant food processing by-products as sources of phenolic compounds with special attention to the role of genetics on the distribution and biosynthesis of plant phenolics, as well as their profiling and screening, potential health benefits, and safety issues. The potentialities in health improvement from food phenolics in animal models and in humans is well substantiated, however, considering the emerging market of plant food by-products as potential sources of phenolic bioactives, more research in humans is deemed necessary. Keywords: phenolic biosynthesis; microbiological safety; phenolic identification; phenolic bioavailability; phenolic antioxidants; cardiovascular disease; cancer; diabetes; obesity; inflammation 1. Introduction Phenolic compounds exist in their monomeric, oligomeric and polymeric forms. Gallic and ellagic acids are found in plant food and their processing by-products as simple phenolics as well as monomeric units of ellagitannins, also known as hydrolysable tannins. Likewise, catechin and epicatechin exist as simple phenolics but are also constituents of proanthocyanidins (condensed tannins). Oligomeric phenolics possess a degree of polymerization (DP) ranging from 2 to 10 while polymers show DP > 10. Conjugated phenolics and their corresponding aglycones are well known and the latter shows higher hydroxylation degree than that of the conjugated form. Furthermore, Int. J. Mol. Sci. 2018, 19, 3498; doi:10.3390/ijms19113498 www.mdpi.com/journal/ijms Int.Int. J.J. Mol.Mol. Sci.Sci. 20182018,, 1919,, 3498x FOR PEER REVIEW 22 ofof 4744 and the latter shows higher hydroxylation degree than that of the conjugated form. Furthermore, monomericmonomeric phenolicsphenolics possesspossess oneone oror moremore aromaticaromatic ringsrings bearingbearing oneone oror moremore hydroxylhydroxyl groupsgroups whilewhile oligomericoligomeric andand polymericpolymeric phenolicsphenolics havehave moremore thanthan oneone hydroxylatedhydroxylated aromatic aromatic ring. ring. SeveralSeveral classesclasses of of phenolic phenolic and and polyphenolic polyphenolic derivatives derivatives have have been been described described in thein the literature literature [1]. The[1]. The terms terms “phenolics” “phenolics” and and “polyphenolics” “polyphenolics” have have sometimes sometimes been been usedused interchangeablyinterchangeably [[2].2]. PhenolicPhenolic compounds compounds are are commonly commonly divided divided into into non- non-flavonoidsflavonoids and and flavonoids, flavonoids, the the latter latter class class is ismost most often often encountered encountered in in the the food food sources sources [3]. [3]. These These chemical chemical bioa bioactivesctives are plant foodfood secondarysecondary metabolitesmetabolites and are primarily primarily related related to to the the plant plant de defensefense against against biotic biotic and and abiotic abiotic stress, stress, pests pests and andpathogens pathogens [2,4]. [ 2However,,4]. However, studies studies in vitro,in vitroas well, as as well in animal as in animalmodels modelsand humans, and humans, also provide also providesupportsupport for their for potential their potential health be healthnefits benefits by lowering by lowering the risk the and/or risk and/orpreventing preventing the onset the of onset chronic of chronicailments. ailments. TheThe existingexisting literatureliterature showsshows aa myriadmyriad of of chemical chemical and/or and/or biochemicalbiochemical mechanismsmechanisms byby whichwhich polyphenolspolyphenols maymay bebe renderrender theirtheir effectseffects [5[5–8].–8]. TheirTheir rolesroles asas antioxidants,antioxidants, scavengersscavengers ofof reactivereactive oxygenoxygen species (ROS), reducers reducers or or chelators chelators of of meta metalsls ions ions and and in inrestoring restoring antioxidant antioxidant enzymes enzymes has hasbeen been well well established. established. Furthermore, Furthermore, inhibitory inhibitory effects effects of of phenolics phenolics towards towards enzymes enzymes related toto metabolicmetabolic disordersdisorders suchsuch asas typetype 22 diabetesdiabetes andand obesityobesity (e.g.,(e.g., αα-amylase,-amylase, αα-glucosidase,-glucosidase, andand lipase)lipase) havehave alsoalso been been highlighted. highlighted. In addition, In addition, polyphenols polyphenols may render may anti-inflammatory render anti-inflammatory and antimicrobial and effectsantimicrobial [9–12]. Therefore,effects [9–12]. some Therefore, authors have some suggested authors thathave phenolic suggested compounds that phenolic are perhaps compounds the most are importantperhaps the non-nutrient most important bioactive non-nutrient compounds bioactive in the compounds human diet [in2]. the human diet [2]. TheThe potentialpotential ofof plantplant foodfood by-productsby-products asas aa sourcesource ofof phenolicphenolic compoundscompounds hashas beenbeen widelywidely recognized.recognized. InIn particular,particular, by-productsby-products fromfrom cereals,cereals, nuts,nuts, oilseeds,oilseeds, freshfresh andand drieddried fruits,fruits, vegetables,vegetables, spices,spices, coffee,coffee, andand tea,tea, amongamong othersothers [[1,13,14],1,13,14], maymay bebe richerricher inin differentdifferent bioactivebioactive phenolicsphenolics thanthan thosethose ofof theirtheir originaloriginal sources.sources. Additionally,Additionally, a a recentrecent studystudy hashas demonstrateddemonstrated that,that, duedue toto theirtheir higherhigher phenolicphenolic contents,contents, winemakingwinemaking by-productsby-products areare ableable toto betterbetter decreasedecrease veryvery low-densitylow-density lipoproteinlipoprotein (VLDL)(VLDL) cholesterolcholesterol andand triacylglycerol triacylglycerol levels levels than than those those of of red red wine wine in in vivo vivo [ 15[15].]. PeanutPeanut skinskin andand grapegrape by-products,by-products, forfor example,example, areare richrich inin proanthocyanidinsproanthocyanidins AA andand B,B, alsoalso knownknown asas condensed condensed tannins tannins [8,16 –[8,16–18],18], whereas wherea pomegranates pomegranate peels and peels seeds and are richseeds in hydrolysableare rich in tanninshydrolysable (ellagitannins) tannins [(ellagitannins)19–21]. Citrus by-products[19–21]. Citr haveus by-products a high concentration have a high of lowconcentration molecular weightof low flavonoidsmolecular weight [22,23], flavonoids and by-products [22,23], from and blueberryby-products and from other blueberry emerging and berries other such emerging as jaboticaba berries (suchMyrciaria as jaboticaba jaboticaba ((Vell.)Myrciaria Berg) jaboticaba and juçara (Vell.) (Euterpe Berg) edulis and Mart.)juçara ( areEuterpe abundant edulis in Mart.) anthocyanins are abundant [24–27 in]. Meanwhile,anthocyanins phenolic [24–27]. acids Meanwhile, are prominent phenolic in wheatacids andare prominent other cereal in by-products wheat and [ 28other,29]. cereal The basic by- structuresproducts [28,29]. of common The basic phenolic structures acids are of common shown in phenolic Figure1. acids are shown in Figure 1. FigureFigure 1.1. Chemical structures structures of of major major phenolic phenolic acids acids id identifiedentified in inpeanut peanut skin skin [12,17] [12,17 and] and grape grape by- by-productsproducts [16,30]. [16,30 ]. BasedBased onon thethe existingexisting knowledge,knowledge, itit isis evidentevident thatthat thethe consumptionconsumption ofof differentdifferent sourcessources ofof phenolicphenolic compoundscompounds