Harvesting and Processing
Fresh vanilla beans are dark green in color and do not impart any aroma because vanillin and other chemical substance are not available in free form at the time of harvest. The beans are ready for harvest when they attain a mild yellow color at the distal end, and it may take 8–10 months to reach the harvesting stage depending on the conditions. Full ripening of the beans leads to splitting and ultimately affects their quality. The beans are to be harvested at the right time, as the immature ones produce inferior commodity. The nonsynchronized flowering and fruiting behavior of the crop leads to selective harvest extending to 1–2 months. Some of the important factors that determine the vanillin content and beans quality are climatic conditions, stage of harvest, and extent of sweating of the pods during curing. During the process of curing, free vanillin is developed in the beans as a result of a series of enzymatic reactions that provide fragrance.
Many processing methods are followed in vanilla-growing countries. However, the Bourbon method of vanilla processing practiced in Madagascar is followed in India, and modified and standardized to suit local conditions. This method is simple and consists of four stages (killing, sweating, slow drying, and conditioning, see Chapter 11) (Krishnakumar et al., 2007, 2008).
Packing
In the final stage of curing, beans are packed in wax paper or any appropriate material and stored in closed boxes for a period of three months or longer to permit the full development of the desired aroma and flavor. Evaluation of different packing methods and methods for keeping up the quality of beans during storage indicated that the beans stored in polyethylene bottle, glass tubes, polypropylene covers (0.011 and 0.035 mm), acrylic boxes, and waxed paper 0.07 mm plus tin were on par with respect to vanillin content and retention of moisture (ICRI, 2006).
According to Purseglove et al. (1981), the primary quality requirement for cured vanilla beans is the aroma/flavor character. The other traits signifying the quality are general appearance, flexibility, size of beans, and vanillin content. Superior quality beans are long, fleshy, supple in nature, very dark brown to black in color, somewhat oily in appearance, strongly aromatic, and free from scars and blemishes.
The quality standards used in India are as per ISO specifications and there are no separate standards specified by Bureau of Indian Standards (BIS). The local traders/ processors have set their own norms based on size of the beans: supergrade beans have a bean size of more than 20 cm, clean without any blemishes; A-grade beans (16–20 cm); B-grade beans (12–16 cm); C-grade (8–12 cm); and low-grade beans comprised of shorter beans, beans with splits, cuts, and wrinkles, and beans with scars/ blemishes. In general, from a healthy plantation, 20–40% of beans produced would be of A grade including supergrade; 30–50% B grade, and the remaining C grade or rejects. In order to attain larger proportion of A-grade beans, farmers restrict the pollination to 10 flowers per bunch and 10–12 bunches per vine. The approximate composition of whole vanilla beans is moisture: 25–30%; protein: 2.56–4.87%; fatty oiclass="underline" 4.69–6.74%; volatile oiclass="underline" 0.0–0.64%; nitrogen-free extract: 30.35–32.90%; carbohydrates: 7.1–9.1%; fiber: 15.27–19.6%; ash: 4.5–4.7%; vanillin: 1.48–2.90%; resins: 1.5–2.6%; calcium: 19.7 mg%; potassium: 16.2 mg%; sodium: 6.7 mg%; phosphorus: 9.5 mg%; and iron: 0.3 mg%.
Analysis of Indian vanilla beans carried out inside and outside the country have shown that the vanillin content was invariably above 2.5% with an aroma and flavor comparable to Madagascar vanilla.
Yield and Economics of Cultivation
The yield performance of vanilla varies depending on the age and method of cultivation. Although vanilla starts flowering from the third year, the yield is harvested in the fourth year. The yield increases till seventh or eighth year and thereafter declines. Under the moderate management, the yield range of a middle-aged plantation will be around 400–500 kg of cured beans per hectare.
Using biometric characters such as vine length (cm), number of leaves, length of yielding area in the vine (cm), length of nonyielding area in the vine (cm), internodal length (cm), vine girth (cm), leaf area (cm²), number of inflorescence, number of beans/inflorescence, bean length (cm), and number of beans/vines, a truncated model yield forecast was developed with a precision of about 93% (Priya et al., 2002).
Vanilla in India is grown largely as an intercrop in plantations and homestead and, hence, the cost of production remains competitive. The cost of production under normal farming situation varies from place to place within the country. One hectare with 1600 vanilla plants needs Rs. 53,000 during the first year of establishment and an average Rs. 34,000 for the second and third year of planting. Thus, the total cost of establishment in 1 ha area is around Rs. 120,000. The cost of maintenance would be around Rs. 37,000/annum. The expected yield of cured beans is around 400–500 kg/ha.
Research and Development Needs
Since the crop is a recent commercial venture with intensive cultivation under varied cropping systems in arecanut/coconut/coffee plantations, new pest and disease outbreaks are posing challenges. Production and postharvest problems need attention to suit the local needs. A major research effort is made by ICRI, Myladumpara, in Idukki district of Kerala, Spices Board. In view of large-scale cultivation both in Kerala and Karnataka, this institute and its regional station at Saklespur, Karnataka are concentrating on the development of good agricultural practices (GAPs), pest and disease management, postharvest, and storage. Some of the recent processing technologies (Krishnakumar et al., 2007) and integrated pest and disease management (IPM/IDM) initiatives (Thomas et al., 2002; Varadarasan et al., 2003) are logical strategies that are helping the farming community.
Healthy planting material production is a major problem and micropropagation technologies have been developed by the University of Calicut, IISR, Calicut, Kerala Agricultural University, and ICRI (Philip and Nainar, 1986; Rao et al., 1992a; Mary Mathew et al., 1999; Chitra et al., 2007).
Distribution of tissue-cultured plants and their field evaluation were taken up by Spices Board in collaboration with the Department of Biotechnology, Govt. of India, New Delhi.
The efforts to propagate and popularize vanilla have resulted in large numbers of farmers taking to vanilla cultivation, particularly in Karnataka, Kerala, and Tamilnadu. Research and developmental activities of the Spices Board have given the required impetus and boost in promoting vanilla cultivation. It is estimated that about 3500 ha under vanilla will yield by 2009–2010.
Since virus problems are rampant in vanilla and are vertically transmitted through planting material, the diagnostic techniques for virus detection are essential. The studies carried out on virus diagnostics at IISR are commendable and can be utilized by the vanilla nurseries (Bhadramurthy, 2008).