Antioxidant Functionality in Plants and Plant Sourced Biomaterials

Review Article

Austin J Nutr Metab. 2020; 7(3): 1081.

Antioxidant Functionality in Plants and Plant Sourced Biomaterials

Nene AG1*, Xuefeng Y1, Hongrong L1 and Ramakrishna S2

¹Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, China

²National University of Singapore, Singapore

*Corresponding author: Nene AG, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China; Email: neneajinkya@gmail.com

Received: May 22, 2020; Accepted: June 15, 2020; Published: June 22, 2020

Abstract

Antioxidants play vital role in neutralizing / removing harmful oxidants produced in human body as well as they are utilized in food technology for applications such as food packaging by introduction into bio films. Plant (land and marine) based biomaterials such as cellulose, starch etc. has tremendous potential in food packaging and other food science applications to enhance food shelf life, protection from external factors and keeping quality intact. Addition of antioxidants; in bio films based on these biomaterials are advantageous as these biomaterials are natural, non toxic and easy availability. Plants are also a source of natural antioxidants and are utilized in dietary, medicinal applications in traditional medicine techniques such as Traditional Chinese medicine and Ayurveda. Present review summarizes recent developments and understanding of ‘antioxidant functionality of plant based biomaterials in food science’. An illustration on health and medicinal benefits of natural antioxidants included in Traditional Chinese Medicine (TCM) and Ayurvedic is incorporated.

Keywords: Antioxidants; Classification of Antioxidants; Mechanism; ROS; RNS; Biomaterials; Traditional Chinese Medicine; Ayurveda

Introduction

Plants containing antioxidant compounds and plant based biomaterials are abundantly available and highly potential for applications in Food science. They can play key roles not only in food packaging, food preservation but also in controlling diseases, diet and nutrition. With respect to food science PFA i.e. Prevention of Food Adulteration a instead a for ward act says that antioxidants are substances which when added to food retards or prevents oxidative deterioration food and does not include sugars, cereal oils, flours, herbs and spices [1]. Market value of food product decreases due to oxidation as it affects on organoleptic properties and destroying essential nutrient properties. Antioxidants help in slowing down oxidation in food as well as human systems. During decades antioxidants are being used in foods as a main strategy to prevent food spoilage [2]. Another approach to limit oxidation in food is active packaging. In this aspect an innovative alternative is the use of active antioxidant packaging systems [3]. Antioxidant agents added to films and edible coatings can modify their structure, functionality to improve chemical stability and protect ozidant sensitive food [4, 5]. Recently, use of active food packaging has been shown prominent effects in controlling food deterioration and in enhancing shelf life at the same time keeping quality of food product intact [2]. Packaging not only play a key role in food supply chain but also acts as barrier to control food from external influences such as oxygen, light, moisture and both from chemical and microbiological contamination [3, 6].

A material with a natural or synthetic origin in contact with a bio system without affecting it can be considered as a Biomaterial. A wide range of biomaterials are in use for diverse applications in medicines and controlled drug delivery, tissue engineering, regenerative medicine, stem cells, biomedical engineering, bioengineering, biotechnology, and health supplements [7-10]. A variety of polymers have been used as biomaterials which are synthesized by plant [10]. For example - Cellulose is one the most abundant natural polymer existing on earth which is also a major constituent in plant cell wall. Cellulose is a source of fibers in fabrics and number of plastics have been made by replacing hydroxyl group present on glucose moiety of cellulose [11]. Various approaches have been developed and used to modify mechanical, structural and biochemical properties of biomaterials for their innovative applications [12].

Lack of antioxidants in food extinguishes ROS i.e. reactive oxygen species, clears the way for diseases (like cardiovascular diseases, cancers, neurodegenerative diseases and inflammatory diseases) as well as food spoilage [13, 14, 3-6]. Including natural antioxidants by means of natural plants that contains antioxidant compounds in diet can solve this problem. Natural antioxidants are helpful in biological functions as they can prevent diseases and also having dietary importance [15-17]. The natural plants or natural antioxidants therefore play an important role in nutritional as well as health benefits [18]. For thousands of years plants have been basis of Traditional Chinese Medicines and Ayurveda and continue to provide remedies with lesser or no side effects on health [19-21].

In this review antioxidant functionality of biomaterials deriving from land plants and marine algae is illustrated with respect to applications in food science. Introduction to antioxidants, free radicals, antioxidant mechanisms are explained in short. Plant based biomaterials are biodegradable, biocompatible and nontoxic and easily available. Some of these plants based biomaterials show antioxidant properties or may possess improved antioxidant functionalities with the addition of either antioxidants or extracts containing antioxidants. These modified biomaterials can be formulated into films, nanoparticles etc. for applications in food packaging. TCM (Traditional Chinese Medicines) and Ayurveda, including plants that are having antioxidant compounds, make them useful in food supplements and medicine.

Antioxidants, free radicals and antioxidant mechanism

Antioxidants-as the name indicates (‘Anti’ meaning against; and ‘Oxidants’ meaning oxidation causing) – are the molecules which deactivates/neutralizes the oxidation preventing free radical production. Antioxidants are not different class of molecules by themselves (say acids, bases, alcohols, aldehydes, ketones, etc.) but represent the property and ability possessed by them to chemically neutralize free radicals so that they become harmless – particularly in living organisms and human beings [22, 23]. Oxidation is a chemical reaction in which one electron (unpaired electron) is transferred from one molecule to an oxidizing agent [24]. Oxidizing agent causes the oxidation of the neutral molecule. Thus, oxidizing agent gains electron while the molecule loses it (electron “leakage”). Converse is true for reduction reaction. A chemical reaction that involves both oxidation and reduction reactions is called as a redox reaction. Oxidation reactions are known to produce free radicals – containing unpaired electron in their outermost shells – (i.e. outermost shell is not completely filled by electrons) – having high chemical reactivity. Such radicals initiate chain reactions in an uncontrolled manner which is harmful and undesired by human/organism body. Antioxidants react with these free radicals thereby terminating the chain reaction and inhibiting other undesired oxidation reactions via oxidizing themselves [25, 26].

Antioxidants are classified according to whether they have been obtained from a natural source (Natural Antioxidants) or have been synthesized (Synthetic antioxidants) (Figure 1).