**3. Zn Deficiency**

Human health problems are caused by zinc deficiency. More than half of the world's population suffers from zinc deficiency. Food fortification improves the trace element content of nutrients and improves nutrition and bioavailability of trace elements. Fortification has made progress in controlling micronutrient deficiencies, but new approaches are needed, especially in developing countries. The process of increasing the natural levels of biologically available nutrients in plants is called bioavailability. Bio-enriched crops are a cost-effective strategy for combating micronutrient deficiencies. Zinc deficiency in plants can be quickly addressed with a variety of effective fertilization techniques.

#### **3.1 Zinc estimation**

Seed samples were peeled and polished according to a standardized protocol for analyzing samples with XRF. Seeds were manually washed and peeled using a Harvest Plus-sponsored JLGJ4.5 non-ferrous huller (Jingjian Huayuan International Trade Co., Ltd., Jiangsu Sheng, China). The peeled brown rice was sieved to remove the broken rice grains, and the complete brown rice grains were cleaned with soft tissue paper. With the hands of a trained person, the sample was lightly rubbed on paper for 1 minute with the hands of a gloved person to ensure that non-rice particles were removed. Each brown rice sample was ground on a specially designed K710 non-ferrous rice mill (Krishi International India Ltd., Hyderabad, India) and the ratio of milled rice was calculated based on the weight of white rice to brown rice. Brown rice samples were polished for 90–120 seconds until the desired whiteness was reached, as white rice is the most common method of consumption. White rice was polished in the same way as brown rice. The time between polishing and washing has been reduced to prevent the bran particles from adhering to the polished grain. Using Energy Dispersive XRF (EDXRF) (OXFORD Instruments XSupreme 8000, Highwycombe Bucks, England), each sample of white rice or white rice (5 g) was analyzed on a Harvest Plus-funded IIRR. The fluorescence intensity of each sample was converted to zinc content (mg/kg) by scanning the sample using a pre-standardized method. Use the zinc concentration of brown rice and white rice [1].

Zinc is an important trace element for normal and healthy plant growth and reproduction. Zinc is classified as a micronutrient due to its low levels of 5100 mg kg1 in plant tissue. Iron, copper, zinc, manganese, cobalt, chromium, iodine and selenium are all important micronutrients in the food chain. Many plant enzymes, including functional, structural, and regulatory enzymes, rely on zinc for their activity. Zinc is also beneficial in plant glucose metabolism, sucrose and starch production, protein metabolism, membrane integrity, and auxin metabolism.

Zinc plays an important role not only in the development of the human immune system, but also in the cellular processes of all living organisms. The recommended daily zinc intake for adults is 15 mg. Zinc acts as a catalyst or structural component of various human and plant enzymes. Zinc is required for many essential enzymes such as RNA polymerase, superoxide dismutase, lactate dehydrogenase, alkaline phosphatase, aldolase, and phospholipase. Zinc deficiency can impair the development of embryos, fetuses, newborns and young children, impair the immune system and delay cell recovery. Zinc deficiency is said to be responsible for the prevalence and disability of children under the age of 5 in low-income countries. Zinc supplementation has been shown to reduce visible diarrhea and respiratory illness in humans. Inadequate intake of zinc in the human diet due to zinc deficiency. Zinc deficiency leads to dire conditions such as hair loss, memory loss, and weakness of the body's muscle tissue that occur in humans. Studies show that adult men need 11 mg of zinc daily and girls need 9 mg. During pregnancy, women should take 1315 mg of zinc daily. 3 mg of zinc per day for babies aged 7 months to 3 years, 5 mg per day for 48-year-old children, 8 mg per day for 913-year-old children Zinc deficiency stores zinc in the shell Because of this, it is common in people who are given grain. Grains are processed into flour. Foods rich in zinc include beef, chicken, almonds, walnuts, oatmeal, yogurt, cheese and milk. The bioavailability of the zinc and iron elements is significantly reduced due to the high content of phytic acid, dietary fiber and tannins, especially in cereal group plants.

It is a term used to refer to the fortification of foods, which increases the content of foods, especially trace elements, thereby improving nutrition and the bioavailability of trace elements. Adding iodine to table salt or adding Fe, Zn, and folic acid to bread crumbs is an example of fortification. The stability of the additive is low, which is a disadvantage in these applications. For example, adding folic acid to rice makes it easier to melt at high temperatures, and cooking rice makes it completely melt. Another drawback is that chemicals can compromise the quality of foods that are mixed in the long term. For example, additives containing iron oxidize and decompose over time, degrading the taste. Applying zinc to soil and/or crop leaves is a rapid way to increase zinc content (**Table 1**). Despite the fact that applying zinc to crops can increase yields and trace element concentrations, many farmers around the world (especially poor countries) do not. In agricultural bio-enhancement (soil/foliar fertilization, etc.), lowering the phytic acid/zinc molar ratio by reducing the phytic acid content of the crop can increase human Zn absorption.

A plant's ability to transport amino acids is critical. Both phloem and xylem are involved in amino acid translocation. As a result, amino acid translocation aids nitrogen recycling between roots and shoots and speeds up the plant's translocation of immobile nutrients, such as Zn. Furthermore, foliar application of urea to zinc fertiliser increases zinc transport throughout plants. Zinc applications will be a separate approach in the soil application of zinc, taking into account the growth periods of the plants.


**Table 1.**

*Different methods used for zinc biofortification in rice crops.*

#### **3.2 Zinc biofortified rice**

Rice is the most important food crop in the world and is trusted by more than half of the world's population. Asia produces and consumes more than 90% of the world's rice. India is the second largest rice producer in the world, producing 112.76 million tonnes from 2017 to 2018. Deficiencies or accumulation of important amino acids, micronutrients and vitamins result from an imbalanced supply that alters human metabolism.

#### *Zinc Biofortification in Rice (*Oryza sativa *L.) DOI: http://dx.doi.org/10.5772/intechopen.104440*

According to the World Health Organization, zinc deficiency is the fifth most common cause of illness in developing countries and the eleventh in the world. Globally, the prevalence of zinc deficiency in soil is estimated to be 20%. Zinc deficiency causes diarrhea and respiratory illness, killing 400,000 people worldwide each year. Zinc deficiency is also associated with poor growth, loss of appetite, skin lesions, taste bud disorders, delayed wound healing, hypogonadism, delayed sexual maturation, and impaired immune response. In India, zinc malnutrition causes 1.31 million disability-adjusted life years (DALYs) to be lost each year. Preliminary analysis of rice zinc bio-enhancements in India shows that of the 1.31 million DALYs lost, 0.142 and 456,000 DALYs under pessimistic and optimistic assumptions when zinc bio-enhanced rice is introduced. I found that I could save money. As a "public good of the world", the International Rice Research Institute and the International Agricultural Research in the form of the Wheat and Corn Improvement Center merged to form the International Agricultural Research Council Group (CGIAR), first carried out and led. it was done. The "Green Revolution" of the 1960s succeeded in improving grain production through the development of high-yielding varieties (HYV). However, HYV grains contain less nutrients. In the case of rice, milling further reduces nutritional levels, namely iron and zinc. Following this, in 1991, CGIAR responded to concerns expressed by the global nutrition community about micronutrient deficiency as a global issue, creating "micronutrient-rich" staple foods under signs of bioenhancement. Started research on. The Harvest Plus Challenge Program was launched by CGIAR in 2003 as a global program aimed at producing bio-enhanced staple crops such as wheat, rice, corn and cassava through plant breeding. Bioenhancement of rice grains with iron and zinc began in 1992 and 1995, respectively.
