17 Article Info Article history Received 19 May 2023 Revised 20 June 2023 Accepted 21 June 2023 Published Online 30 June 2023 Keywords Nutraceuticals Food processing methods Free radicals Diseases Antioxidant mechanisms Effect of different food processing techniques on native antioxidants Sabbu Sangeeta  , Poonam Yadav, Preethi Ramachandran, Sweta Rai and Gaurav Chandola Department of Food Science and Technology, College of Agriculture, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar-261345, Uttarakhand, India Abstract Antioxidants are the natural molecules that help to neutralize harmful free radicals in our bodies linked to multiple illnesses, including diabetes, heart disease, and cancer. Generally, fruits and vegetables are considered as the ideal source of antioxidants like vitamin C, vitamin E, lycopene, flavonoids, etc., but some other plants source such as tea, coffee, beans, etc., are also rich in antioxidants. However, to meet the demands for convenient, cheaper, and readily available food, a number of conventional and novel food processing techniques are employed to transform the natural fresh foods into value added products including, jam, chutney, jelly, RTS beverages, pickles, candies, etc. While these processing methods bring about numerous advantages, such as improved convenience and preservation, they also have the potential to lead to the loss of essential naturally occurring food components, particularly bioactive compounds. A review discussing the effects of different processing methods on the natural antioxidants of food and their effect on health has been discussed hereunder. Copyright © 2023 Ukaaz Publications. All rights reserved. Email: ukaaz@yahoo.com; Website: www.ukaazpublications.com Journal of Phytonanotechnology and Pharmaceutical Sciences 3(2): 17-26, 2023 Online ISSN:2583-0376 http://jpps.ukaazpublications.com DOI: http://dx.doi.org/10.54085/jpps.2023.3.2.4 Journal of Phytonanotechnology and Pharmaceutical Sciences Corresponding author: Dr. Sabbu Sangeeta Department of Food Science and Technology, College of Agriculture, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar-261345, Uttarakhand, India E-mail: sangeeta_pantnagar@yahoo.com Tel.: +91-9359566639 Review Article : Open Access 1. Introduction A balanced and nutritious diet is the cornerstone of good health. Cereal, pulses, milk, and fruits and vegetables make a balanced healthy diet. According to nutritional pyramid, eating 5 servings of fruits and vegetables in a day provide essential nutrients such as vitamins, minerals, fibre, and antioxidants which improves our immune system and helps in preventing many diseases such as diabetes, obesity, heart disease and even certain types of cancer. Among different nutrients, fruit and vegetables are denser in antioxidants as shown in Figure 1 (Aries et al., 2022). Antioxidants help to prevent the oxidation process. Antioxidants are compounds that scavenge free radicals in the human system by acting as a defense system to the body against the damages caused by free radicals and reactive oxygen species (ROS). Oxidation is a chemical reaction that can produce free radicals and ROS, which potentially causes serious damage to cells of the body (Mititelu et al., 2020; Sharifi-Rad et al., 2021). ROS are usually produced either by normal cell metabolism or exposure to external factors.They are subsequently responsible for premature ageing and various diseases like cardiovascular and degenerative diseases (cataracts, Alzheimer’s disease, and cancer). There are two types of antioxidants, i.e., endogenous (found in body itself) and exogenous (intake from outside such as food). Various sources of exogenous antioxidants with their mechanism are presented in Table 1. Natural antioxidants are found in varying category of food, including fruits, vegetables, tea, coffee, and other plant-based diets. Worldwide dietary recommendations include the consumption of fruits and vegetables as a strategy for disease prevention, provide macro as well as micronutrients and many phytochemicals along with their antioxidant properties (Ali et al., 2021). 2. Antioxidants as pharmacological agents Many biological processes such as breathing, metabolism of biomolecules, digestion, etc., take place in living body continuously, for the generation of energy which are responsible for producing harmful compounds such as free radicals, ROS, reactive nitrogen species (RNS), etc. (Pizzino et al., 2017). Under stress conditions, formation of ROS and RNS is quite common phenomenon, that produces oxidative stress and irreversible alterations in cell due to redox imbalance. Oxidative stress is one of the major cause developments of damage in cell structures which includes changes in membrane structure, proteins, lipids, and DNA, etc. These types of damages alter the cell functions, leading to variety of cellular responses through the formation of secondary reactive species, affecting the health of cells. These secondary reactive spices play important role in development of chronic diseases in human being like cancer, cardiovascular, liver, and neurological disorders, etc., as depicted in Figure 2 (Rudrapal et al., 2022). The defense mechanism of antioxidant comprises of different mechanisms that includes: (a) delaying or inhibiting free radicals’ production, (b) free radical scavenging, (c) changing free radicals into less toxic compounds, (d) delaying the formation of secondary toxicactive species, (e) interrupting the chain propagation reaction (chain breaking antioxidants), (f) boosting the endogenous antioxidant defense system through synergism with other antioxidants and (g) chelating metal ions (Adwas et al., 2019). The endogenous antioxidant defense system of the body is improved to reduce the undesirable effects of free radicals, ROS and RNS by supplementing,