Volatile oil content in kernel ranged from 1.57 to 7.67 per cent. Similarly, mace oil content ranged between 2.05 and 9.33 per cent. Genotype, Acc.22 (9.33%) recorded highest mace volatile content. Genotypes, Acc.5, Acc.6, Acc.8, Acc.22 and Acc.34 registered high amounts of both kernel and mace volatile oils (Table 1). Oleoresin content in kernel varied from 18.59 to 36.20 per cent. Significantly the highest recovery of kernel oleoresin was recorded in Acc.40. In mace, oleoresin content varied from 11.38 to 31.66 per cent. Highest recovery of mace oleoresin was recorded in Acc.4. In all the genotypes, content of oleoresin was high in kernel compared to mace. In Acc.4, both the kernel and mace oleoresin contents were high. Fixed oil content in the kernel of various genotypes varied from 17.79 to 44.80 per cent. Significantly very high recovery of fixed oil was recorded in Acc.22.
Abdurrasheed and Janardanan (2009) have recorded the fixed oil content of 33.80 per cent in nutmeg collected from northern districts of Kerala. Interestingly, genotypes, Acc.8, Acc.22 and Acc.38 were both high yielding as well as of high quality. These three genotypes could very well be categorised as high performing types which could be utilised for commercial cultivation, pharmaceutical applications and industrial utilisation.
Total volatile oil constituents of the genotypes ranged from 68.96 to 90.49 per cent in kernel and 83.96 to 93.89 per cent in mace (Tables 2 and 3). GC/MS analysis showed the presence of 20 and 24 constituents in kernel and mace oils, respectively. This variation in per cent composition of constituents may be due to genetic makeup of the accessions.
The prime compounds in the oil were myristicin, elemecin, sabinene and safrole. Apart from these, accessions also recorded higher percentages of alpha-pinene, beta-pinene and L-4-terpineol in kernel and mace oils.
Chirathaworn et al., (2007) identified myristicin, eugenol, isoeugenol and elemecin as the major bioactive compounds in nutmeg oil. Myristicin content ranged from 2.98 to 12.84 per cent in kernel oil and 1.57 to 18.87 per cent in mace oil. Elemecin content was to the tune of 4.31 to 22.48 per cent in kernel oil and 1.39 to 27.86 per cent in mace oil. It was interesting to observe that, monoecious genotype, Acc.(H) 1 had significantly higher myristicin and elemecin in both kernel as well as mace oils. Safrole content varied from 2.44 to 4.64 per cent in kernel oil and 2.96 to 4.89 per cent in mace oil. Sabinene content ranged from 1.06 to 11.75 per cent in kernel oil and 4.89 to 16.20 per cent in mace oil. Acc.8 recorded significantly the highest sabinene in both kernel and mace oils. The notable difference between the kernel oil and mace oil was that, kernel oils contained higher level of L-4-terpineol, whereas it was low to medium in mace oils.
Genotypes, Acc.5 and Acc.(H) 1 were high myristicin as well as high elemecin containing chemotypes. Genotypes, Acc.9 and Acc.36 were in the low myristicin group. Acc.9 was also low in elemecin along with Acc.35. High sabinene combined with low myristicin was the intrinsic quality attribute of Acc.9. Myristicin, elemecin and safrole are the hallucinogenic compounds in nutmeg oil, whereas sabinene imparts sweetness to the products. The present study has brought out high as also low hallucinogen containing genotypes along with high sabinene containing types. Higher content of myristicin, elemecin and safrole is preferred by the pharmaceutical sector, while sweet nutmegs with high sabinene content are preferred in the food sector.
Lawrence (2000) also indicated about the variability in the constituents of kernel and mace oil.
Total number of compounds increased from 20 to 27 in kernel oil after one year of storage (Table 4). Among the samples, one sample (Acc.5) recorded overall per cent increase in constituents (5.10%) whereas the other two samples (Acc.38 and Acc.(H) 1) showed losses of constituents on storage. Among the seven major constituents, only myristicin and elemecin contents increased substantially on storage in all the three samples. Both these compounds have extensive applications in the ayurveda and pharmaceutical sectors. Alpha-pinene, sabinene and beta-pinene contents decreased in all the three samples upon storage. Percentage of L-4-terpineol increased in Acc.5 and Acc.(H) 1 where as content of safrole increased in Acc.(H) 1. On storage of kernel volatile oils, nine additional compounds were detected.
One year storage period in four samples of mace volatile oil detected the presence of 30 compounds as against (Table 5) 24 compounds in fresh mace oil. Maximum percentage of change was recorded in Acc.21 (14.63%) and minimum in Acc.11 (1.92%). The content of elemecin increased in all the four samples of mace oil whereas myristicin level increased in three samples except Acc.21. Alpha-pinene, sabinene and bete-pinene contents decreased in all the four stored samples. On storage of mace oils, 13 additional compounds were detected. The increase or decrease in the relative concentration of volatile constituents may be due to the chemical transformations that occur during storage.
Hafiz et al., (2019) studied the post storage changes of volatile compounds in air and sun dried raisins and opined that aroma profile increased after storage for 12 months.
