Cultivation of cactus pear for higher income in arid zone

Abstract

Climate change has become one of the biggest challenges for the sustainable crop production. Prolonged droughts and desertification are among the issues faced by Indian hot arid zone where the rural poor and smallholders are most heavily affected. If people are to survive in these ever harsher conditions, their crops need to withstand drought, high temperatures and poor soils. Cactus crops are gaining increasing interest across the globe, in particular cactus pear or prickly pear (Opuntia ficus indica (L) Mill.) because of its unique characteristics which provide resilience to the harsh ecological conditions. Cactus pear is able to grow on land where no other crops are able to grow; it can be used to restore degraded land. It is the only crop that can be relied on when everything else fails. Cactus pear is grouped as CAM plant (Crassulacean Acid Metabolism), a photosynthesis mechanism evolved in some plants as an adaptation to arid conditions. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but open at night to collect carbon dioxide (CO2). At night carbon dioxide is stored as 4 carbon acid malate in cell vacuoles. The malate is transported to chloroplasts where it is converted back to CO2 during day which is used in the process of photosynthesis (Ting, 1985). The cactus pear plants though shallow rooted but have capacity to absorb and store water in its parenchyma even under unfavourable climatic conditions due to high mucilage production in both cladode and fruits Besides, peculiar adaptations to water scarcity and high as well as low temperature is because of reduced leaf tissues and cuticular wax covering of cladodes and fruit surfaces. (Saroj et al, 2017). The cactus pear fruit is an oval, elongated berry, with a thick pericarp and a juicy pulp and, in general, many hard seeds generally known as tuna. The fruits are of different colours, such as red, purple, orange, yellow and green in colour which show the presence of various antioxidants. The high sugar and low acid blend of the fruit makes it delicious and palatable. The pericarp of ripe fruits accounts for 33% to 55%, while the pulp is 45% to 67%, and seeds 2% to 10%. The pulp is the edible part of the fruit and is composed of water (84% to 90%) and reducing sugars (10% to 15%). The pH value of fruits ranged (5.3 to 7.1) and the very low acidity (0.05% to 0.18% in citric acid) of the pulp, which strongly influences the processing operations. Sugars range from 10°Brix to 17°Brix and are mainly of the reducing type (Russel and Felker, 1987; Stintzing et al., 2003). Cactus cladode (nopal) is rich in pectin, mucilage, minerals, polyphenols, nicotiflorin, vitamins, polyunsaturated fatty acids (palmitic acid, oleic acid, linoleic acid, linolenic acid etc.) and amino acids (glutamine, leucine, lysine, valine, arginine, phenylalanine and isoleucine). The nopal contains antioxidants and various flavonoids, particularly quercetin 3-methyl ether, a highly efficient radical scavenger. Chemical characterizations of nopal have studied by several workers and reported that it contains vitamins and minerals. Dehydrated nopals contain high levels of potassium content. Considering the lactose intolerance in certain parts of the population, nopals could be an alternative as source of Calcium. Cactus nopal pulp has numerous compounds (dietary fibre, vitamin C, phenolic compounds) with the potential to provide important benefits like intestinal, cardiovascular, hepatic health, antioxidant activity and cancer prevention. The fresh young pads so called nopal are excellent source of proteins including essential amino acids and vitamins. The value added products of cactus pear could also supplement to nutritional security and human health. The succulent vegetative parts are called as pads or cladodes which are modified stem.