MSc

Nutmeg (Myristica fragrans Houtt.) belongs to the family Myristicaceae. Nutmeg produces two spices of commerce namely nutmeg, dried kernel of the seed and mace, the dried aril surrounding the seed. Nutmeg rind constitutes 80 to 85 per cent of its whole fruit weight and at ripe stage it has an acidic astringent taste with aromatic flavour. If it can be converted to attractive value added products it will be a boon to nutmeg farmers.
Hence the present study was endeavoured to access the proximate composition of nutmeg pericarp and possible ways to consider it as a value-added commodity, with nutritional and pharmacological benefits.
The color of rind described using Universal Colour Language (UCL) was pale greenish yellow (RHS 164C 71) during harvest and it changed to moderate orangish yellow when kept under room temperature. The texture of the nutmeg rind was 1.85 Kg/cm2 i.e., 4.1 lbs/sq. inch.
Nutmeg rind constitutes 75 to 80 per cent of whole fruit weight and has a high moisture content of 88.45 per cent. The acidity recorded in rind was 1.43 per cent, total phenol (35.20 mg/100g) and tannin (33.80 mg/100g). The total soluble solid (TSS) of nutmeg rind is less (3.38° brix) and therefore it has low total sugars (2.69 %). In the present study, the pericarp showed the presence of 1.25 g/100g protein, 2.55 per cent of crude fibre and 0.78 per cent pectin. Nutmeg rind is a poor source of ascorbic acid (11.45 mg/100g), starch (0.95 g/100g) and carotene content (37.82 μg/100g).
The nutmeg rind had high iron content (607.800 mg/Kg) and the presence of other minerals like potassium, calcium, magnesium, copper, zinc, and manganese were also observed.
The antioxidant activity of nutmeg rind was compared to that of gallic acid and was found that the IC50 value of sample was 120 μg/ml while that of standard was 1.25 μg/ml showing medium antioxidant activity.
The nutmeg rind oil is colourless in nature and the oil recovery percentage in fresh sample is 0.05 per cent and that of dried sample is 0.10 per cent. The GC-
MS profiling of the nutmeg rind oil exhibited a seven peak chromatogram and the compounds found were myristicin, elemicin, terpenen-4-ol, alpha-terpineol, methyl (Z)-N-hydroxybenzene carboximidate, 1,2–dimethoxy–4[(Z)-1- methoxyprop-1-enyl] benzene and methyl laurate. The oleoresin recovery was estimated to be 3.17 per cent.
The pericarp was screened for phytochemicals and showed that flavonoids, saponins and terpenoids were present in petroleum ether, acetone and methanol extracts of nutmeg rind.
Considering all the biochemical constituents, 3 per cent salt water treatment for 48 hours was found to be the best pre-treatment for product development. The value added products prepared were wine, powder, candy, chunk, syrup and jam. Wine prepared using rind, sugar and water in the ratio 1:1:1 was selected as the best after biochemical estimation and organoleptic evaluation. The best process for making the nutmeg rind powder is found to be sun drying powder and was mostly accepted due to its sensory and biochemical constituents. Nutmeg rind was also used for the preparation of two types of candy, titbits and flakes. The biochemical analysis showed that candy titbits are of better quality while the flakes scored highest in organoleptic evaluation. The chunks prepared by immersing the pre-treated nutmeg rind in 70° brix sugar solution for 48 hours scored better organoleptic scores and sensory evaluation. The juice extracted from pre-treated nutmeg rind by using pressure cooked and hot water extract had least preference. In the case of jam, the pulp and sugar ratio of 1:2 gained the maximum score for organoleptic evaluation.