Indian J. Plant Physiol. Vol. XXXV, No.3. pp.231 237 (Sept. 1992) DETERIORATION OF PHYSICO CHEMICAL PROPERTIES OF CHILGOZA (PINUS GERARDIANA WALL) SEED DURING STORAGE PUSHP LATA SINGH, M.N. GUPTA AND A.L. SINGH Botany Department, Agra College, Agra (U.P.) Received on 22 Nov., 1991 SUMMARY The physico-chemical changes in the chilgoza (Pinus gerardiana WaU.) seed during storage for a period of one year were studied. Maximum deteriorative changes were observed in the seed during June to Nov. the latter half of the storage period. Seed turned dark blackish brown in colour and emitted rancid moldy odour. Thc moisture, gross weight and oil content of seed was markedly reduced. The oil changed from pale yellow to dirty range in colour, emitted rancid odour and changed from semi drying to non drying nature, The free fatty acid contents, saponification and reroxide values of oil increased with storage while iodine value decreased. The total nitrogen, protein, non reducing sugar and total sugar of seed showed a marked reduction towards the end of the storage period. INTRODUCTION Pinus gerardiana a gymnospermous plant yields delicious edible seed, known as "Chilgoza", High oil (49.9%). protein (15,9%) and carbohydrates (21.6%) make the chiigoza of great economic value which generally get heavily infected by fungi during its transportation and storage (Singh. 1982; Singh and Gupta 1989), It is commonly observed that the fungi alter the physical and chemical nature of the various stored products by decreasing their germinability, causing heating and mustiness, producing toxins which if consumed may be injurious. The informations on the chemical changes brought about in the protein. carbohydrates, fats and vitamins in chilgoza seed under storage are lacking, The present experiment was undertaken to tindout the changes in colour, odour and gross weight of seed, oil and its quality, total nitrogen,protein and sugars of chilgoza seed during storage round the year, National R~~ ~ntre for a""un(lnut, Junapdh 36l 001. India
.232 PUSHP LATA SINGH et ol. MATERIALS AND METHODS The fresh chilgoza (Pinus gerardiana Wall) seeds were stored in finely webbed gunny bags of one kg each under ambient laboratory condition in five replicates. The following physico, chemical characters of seed were determined from the fresh sample before storage and also from the stored samples at an interval of three months for a period of one year. Physical examination of seed and oil: The seeds were carefully observed for the changes in colour, weight, odour and moisture content. The colour shade of seed was determined with the help of Paul's standard colour dictionary (Paul. 1950). The weight was determined by weighing 100 randomly selected seed per lot. The odour of the seed was recorded without removing the testa. For determination of seed moisture 109 seed was kept in an oven for 48 hrs at 60 C, cooled in a desicator and weighed. The process of heating and weighing was repeated till the weight became constant and the percentage seed moisture was calculated on dry weight basis. The.' oil from chilgoza seed was extracted following soxhlet's method (AOAC, 1960). The percentage change in the oil content during storage was worked out. The oil free seed residue was used for the estimation of sugar and nitrogen. The colour, odour and viscosity of the oil extracted from fresh as well as stored samples were determined. The viscosity was measured following the method described by Iswarah (1980). Chemical analysis ofoil: The oil extracted from fresh as well as stored samples was subjected to estimation of free fatty acid by KOH method, iodine value by Wij's titration method, saponification value by HCI titration method and peroxide value following standard method as described in AOAC (1960). The reducing sugar was estimated by Nelson's method modified by Somogyi (1952) and tbe total sugar following Scott's method (1960). For non reducing sugar the amount of reducing sugar was substracted from the total sugar. The total nitrogen of seed was estimated following Snell and Snell (1954) using Nessler's reagent and the protein content was calculated by multiplying the total nitrogen with 6.25. Physical changes ill seed RESULTS AND DISCUSSION The colour of the fresh seed was light brown which gradually became darker in shade with storage period. and at the end of a year it was dark brown (Table-I). The changes in the colour of the testa specially during the later part of storage was largely due to heavy infestation by a number of fungi which secreted of certain pig
ments that got dissolved in the surface film of water. However, Abdul-Baki and Anderson (1972) working with certain grain have suggested it to be due to the oxidation of the polyphenols of the stored materials. The odour of the seed started changing from pleasant oily to slight acrid and finally to rancid moldy (Table-I). Rapid change in odour was, noticed during the last six months. The 100 seed weight of fresh sample was 32.3 g which gradually decreased to 109 at the end of storage period (Table-I), The seed moisture increased during the last six months. Chemical changes The oil extracted from the fresh sample was pale yellow in colour which gradually became darker in shade showing lemon yellow, mustard yellow at different storage period and finally dirty orange at the end of one year storage (Table-II). The oil from fresh sample emitted delicate terpentine pleasant oily odour which gradually changed to moldy, acrid moldy and rancid odour at the end of the storage. LaUtha kumari et al. (1971) working with groundnut suggested that rancidity in oij developed during storage with increase in the free fatty acid contents and was also proportional to the seed moisture content and fungal growth. During the first six months of storage there was practically no change in the viscosity of the oil but it increased at the end of 9 months and remained almost similar upto 12 months (Table II). The increase in viscosity of the oil may indicate its conversion from semidrying to nondrying nature. Table I. Effect of storage on the physical characteristics of chilgoza seed* Time of Seed colour Odour loo-seed Seed R.H. (%) storage weight (g) moisturee of storage (Months) (%) condition 0 Light brown Pleasant oily 32.3 8.2 59.0 3 Light brown Pleasant oily 30.5 9.2 58.0 (5.8) 6 Slightly dark Acrid 24.0 8.7 47.1 (18.9) 9 Dark brown Rancid moldy 15.8 15.3 80.3 (49.S) 12 Dark brown Rancid moldy 10.0 13.6 61.4 (66.9) Mean of 10 replicates. Figures in parentheses indicate percentage loss in seed-weight.
J.vsiip LATA SiNGH et ai. Table II. Changes in the colour, relative viscosity and odour of the chilgoza oil during storage Time of Colour of oil Relative Odour Sloraae viscosity (Months) Visual Colour of dictionary code o Pale- yellow 9-B-l ± Delicate terpentine 3 Lemon yellow Urt-l-Reedy ± Terpentine tlavour with mold odour 6 Mustard yellow 9-7-5-10nguil + Acrid moldy 9 Mustard yellow 9-0-6 +++ Rancid with light brow nish tinge 12 Dirty orange 9-L-6 Golden ++++ Highly rancid yellow.~--------------- Dictionery of Colour (Paul. 1950). Table III. Effect of storage on the chemical chluacteristic of oil in chilgoza seed Time of Oil corltent Free fatty acid Iodine value Saponification value Peroxide value storage (%) value (g iodine/too g (mg KOH/I! oil) (meq terrcide/ (MoDlhs) (mg KOH/g oil) kg oil) oil) o 3 50.4 50.0 3.37 5.61 (66.6) 121 115 (-4.2) ]92 224 (16.7) 9.4 9.4 6 9 12 49.8 45.8 39.9 (-19.9) 7~74 (130) 15.71 (364) 31.42 (833) 113 (-6.2) 108 (-10.4) 98 (-]8.7) 295 (53.4) 331 (72.0) 407 (112) 9.6 (2.1) 10,0 (6.4) 10.4 (10.6) The oil content of 'ieed decreased from 50.4% to 39.9% within 12 months of storage (Table-III). During the first six months there was very little change but it was very fast during last 6 months. Interestingly fungi like Aspegillus flavus, A. niger, A. fumigatus. Curvularia lunata, Fusarium oxysporum, F. solani, Penicillium cyclopium and Trichoderma harzianum were found to increase their population in proportion to the percent loss in oil content. Of these A. flavu$, A. niger, Curvularia lunata
PHYSlCo-CHEMiCAL CHANCES IN cmi:.goza SEED and Penicillium cyctopium dominated during the later half of the storage and producing more active lipase in vitro (Singh. 1982) resulting in enzymatic hydrolysis of oil into free fatty acids. This was well supported by increase in free fatty acid content (Table-III). The free fatty acid (FFA) content extracted from the srored seeds sho"ed an appreciable increase over fresh seed (Table-III). The enzymatic breakdown of oil to free fatty acids during storage resulted in the increasing amount of free fatty acids consequently their oxidation into the peroxides also increased as it was indicated by increase in the peroxide value. Such changes occured during later period of storage. The iodine value of the oil from the fresh sample was as high as 121 indicating that the oil was highly unsaturated and of semidrying nature with storage, however, there was a gradual reduction and it was only 98 at the end of the year with decreasing Iodine value less than 100, the oil became more and more saturated and changed from semidrying to nondrying nature. Interestingly, the maximum decrease (9.2%) in the Iodine value was observed during 9 and 12 months after storage. A possible correlation between the Iodine value and unsaturated fatty acids was reported by Knowles (1965) in sunflower. The saponification and peroxide values of oil increased with increase in storage period. The saponification value of the oil extracted from the fresh sample was 192 which increased with increase in storage period (Table-Ill). Sharma (1981) while working on seasame oil noted that increase in FFA caused increased in saponification values. The peroxides value of oil remained unchanged upto 3 months of storage but later it gradually increased. Sugars: The reducing sugar content of seed increased during the first six month after the storage period and decreased later showing a fluctuating trends. This was due to selective utilization of carbohydrates by fungi and its further breakdown. The non-reducing and total sugars, on the other hand. decreased with increasing storage period (Table-IV J. The enzymatic hydrolysi~ of the complex sugars into the simple ones (reducing sugars) and their slow and preferential utilization by the fungi may be the cause of reduction in total sugars and increase in reducing sugars. Sinha and Prasad (1917) reported that the reduction in carbohydrate contents of differing food commodities during storage was due to the amylolytic activity of different pathogenic fungi. Nitrogen and Protein contents: The total nitrogen content of the fresh sample was 2.55 % which decreased in all the four phases of storage but the rate of reduction varied with a maximum reduction during the last phase of storage (Table-IV), Likewise the protein contents also decreased with increasing storage time and the initial
236 pbshit lata SINGH et ai. Table IV. Effect of storage on the sugar, total nitrogen and protein contents of chilgoza seed Time of % Sugars *Total nitrogen Protein content storage --- (%) (%) (Months) Reducing Non-reducing Total 0 0.97 4.13 5.10 2.55 15.9 3 1.05 1.95 3.00 2.40 15.0 (8.2) (-53) (-41) (-5.9) (-5.6) 6 1.09 1.11 2.20 2.30 14.4 (12.3) (-73) (-57) (-9.8) (-9.7) 9 0.99 0.51 1.50 1.70 10.6 (- 87) (-71) (-33.2) (-31.9) 12 0.97 0.13 1.10 1.25 7.8 (-97) (-78) (-50.7) (-48.7) "'-- value of 15.93% came down to 7.81 % after 12 months of storage (Table IV). The fungi associated with the seed secreted fairly active protease enzyme in vitro (Singh 1982) which was involved in the enzymatic breakdown of protein into amino acids and their utilization resulted in its continuous decline. ACKNOWLEDGEMENTS We gratefully acknowledge Dr. S.M.L. Gupta, Head, Chemistry Department, Agra College, Agra, for extending facilities and Dr. Mukhtiar Singh for his help in conducting experiment and critical examination of observations during the course of investigation. REFERENCES Abdul-Baki, A.A. and J.D. Anderson (1972). Physiological and biochemical deterioration of seeds. In seed biology Ed. T. Kozlonski), Vol. II. pp. 283-315, Academic Press, New York. A.O.A.C. (1960). Official methods of Analysis. 9tb ed, A.O.A.C. Washington. D.C. Iswarab, V. (1930). A Laboratory hand book for Agrlcllitural analysts. (Methods and Interpretation of results). Today and Tomorrow Printers and Publisher New Delhi, India. Knowles, P.F. (1965). Variability in oleic acid and linoleic acid contents of safflower oil. Econ. Bot., 19: 53-56. Lalitba Kumari, D., Govindaswamy, C.V. and Vidyasa Karan, P. (1971). Effect of seed-born fungi on the pbysico-cbemical properties of groundnut oil. Indian Phytopath. 24: 283-289. Paul, M. (1950). Dictionary of colour, second edition. Me Grew Hill Book Comp. Inc. New York.
PHYSICO-CHEMICAL CHANG IS IN CHJI.GOZA SEEn 237 Scott, F.G. (1960). Effect of supraoptimal boron levels on respiration and carbobydrates metabolism of Helianthus annuus. L. Plant Physiol. 85: 653-668. Sharma. K.D. (1981). Biodeteriorations of sesamum oil in situ by fungi. Indian Phytopalh 34: 50-53. Singh, P.L. (1982). Studies on the seed-borne disorders of ehilgoza (Pinus gerardiana Wall.) during storage. Ph.D. Thesis, Agra University, Agra. Singh, Pushplata and Gupta, M.N. (1989). Internal mycoflora associated witb different palls of 'Fresb' and 'Market' samples of Piuus gerardiana seeds. J. Indian Bot. Soc., 68: 155 157. Sinha, M.K. and Prasad, T. (1977). PhYlopalh., 30 : 70.72. Deterioration of'arhar' seeds by Aspergillus jlal'us. Indian Snell, P.D. Snell, C.T. (1954). Colorimetric methods ef aralysis, Vel. IIl, D. Van Ne~traJld Company inc. New Delhi. Somagyi, M. (1952). Notes on sugar determination. J. Bioi. Chtm., 195 : 19 23.