Raw green mangoes are mainly used in the processing of pickles, chutneys and dehydrated powder (Amchur). Raw mango is known to possess good amount of citric and mallic acid along with other nutrients (Rao et al 2012). Dry mango powder also known as Amchur is a fruity spice used to add citrusy flavour to various Indian foods. It is a special Indian spice that is made by grinding dried mango slices. The powder is known to attract the acidic and spicy flavour of the unripe mango and extend it in all the curries and chutneys in Indian cuisines. Amchur is recognized at national level by ISI as one of the spices and condiments listed in the IS specification. Dehydration of raw mangoes for preparation of Amchur was studied in detail by number of workers (Dabhade and Khedkar 1980c, Goyal et al 2006, Mehta and Tomar 1982). Packaging of Amchur is done in friction top tins or poly-lined gunny bags. Lot of variation is observed in quality of Amchur prepared in different states of the country with regards to colour, texture and acidity. In the present study an attempt has been made studying changes occurring during storage of Amchur packed in 100, 200, 300 and 400 gauges high density polyethylene.

Seventy five per cent mature mango fruits of cv Alphonso were obtained from Department of Horticulture, Konkan Krishi Vidyapeeth, Dapoli, Maharashtra during 2008 and 2009. The fruits were washed, peeled and cut lengthwise into slices of 1.5 cm. The slices were treated as per the treatments, dried/dehydrated and powdered by grinding, sieved and packed in 100, 200, 300 and 400 gauge HDPE bags of 8 cm x 8 cm size and stored at ambient temperature. These were analyzed for acidity, starch, ascorbic acid and beta-carotene at three months interval during storage period of nine months. The experiment was laid out in FCRD with 14 main treatments, four sub-treatments and three replications.

The main treatments were T₁ (Blanching slices for 5 min + 5 min dip in 0.5% KMS + sun drying), T₂ (Blanching slices for 5 min + 5 min dip in 1.0% KMS+ sun drying), T₃ (Blanching slices for 5 min + 5 min dip in 1.5% KMS + sun drying), T₄ (Blanching slices for 5 min + 5 min dip in 0.5% KMS + cabinet drying), T₅ (Blanching slices for 5 min + 5 min dip in 1.0% KMS + cabinet drying), T₆ (Blanching slices for 5 min + 5 min dip in 1.5% KMS + cabinet drying), T₇ [Slices dip in 0.5% KMS for 5 min + sun drying (no blanching)], T₈ [Slices dip in 0.1% KMS for 5 min + sun drying (no blanching)], T₉ [Slices dip in 1.5% KMS for 5 min + sun drying (no blanching)], T₁₀ [Slices dip in 0.5% KMS for 5 min + cabinet drying (no blanching)]_, T₁₁ Slices dip in 1.0% KMS for 5 min + cabinet drying (no blanching)], T₁₂ (Slices dip in 1.5% KMS for 5 min + cabinet drying), T₁₃ [No blanching + no KMS + sun drying (control)], T₁₄ [No blanching + no KMS + cabinet drying (control)] and four sub-treatments were P₁ (100 gauge polyethylene), P₂ (200 gauge polyethylene), P₃ (300 gauge polyethylene), P₄ (400 gauge polyethylene).

The data on changes in moisture, TSS, acidity, reducing sugar, total sugar, ascorbic acid, starch and beta-carotene of Amchur during storage are presented in Table 1.

Moisture: Lowest moisture content was reported in treatment T₁ (9.00%) and packaging material P₄ (9.41%) and was found to be best as compared to all other treatments and packaging materials. The reason for lowest moisture content in 400 gauge packaging material could be attributed to more thickness of the polythene. Highest moisture was reported in treatment T₁₄ (12.59%) and packaging material P₁ (12.59%). The gain in moisture during storage is attributed to moisture absorption from the atmosphere and permeability of the polythene bags to moisture vapour. Analogus results to present findings are reported by Dhabhade and Khedkar (1980a, 1980b) in Amchur.

TSS: Highest TSS was noticed in treatment T₆ (9.12°B) which was at par with T₅ (9.08°B) and significantly higher over rest of the treatments. Packaging material P₄ recorded the highest TSS (8.26°B). The increase in TSS during storage could be attributed to the conversion of non-reducing sugar into reducing sugar by acids present in the product. However Raorane (2003) recorded no change in TSS of Kokum rind powder prepared from rind of Kokum after preparation of syrup after 8 months storage in glass jars.

Acidity: Acidity decreased in all treatments irrespective of the packaging material at 3, 6 and 9 months storage. Maximum acidity was recorded in T₁₃ (13.83%) and was found to be significantly superior over all other treatments. P₄ packaging material recorded highest acidity (11.40%) which was significantly superior over all other packaging materials. Treatment combination T₁₃P₄ recorded highest acidity (13.99%). Interaction effects were found significant throughout the storage period. Lowest acidity was recorded by T₁ and packaging material P₁ during the complete storage period. Amchur prepared from treatment T₁₃ and packed in P₄ registered highest acidity compared to other treatments and packaging materials which could be due to absence of blanching whereas lowest acidity was recorded by T₁P₄ which could be due to loss of acid during blanching process. The decrease in acidity during storage period could probably be due to disappearance of SO₂ from the Amchur. Similar results were reported by Dabhade and Khedkar (1980a, 1980b) in Amchur.

Reducing sugar and total sugar: At 9 months storage period, maximum reducing sugar was found to be in T₁₄ (15.65%) and was significantly superior over all other treatments. The interaction effects were found to be significant. Amchur packed in packaging material P₄ recorded highest reducing sugar (12.13%) and was significantly superior over all other treatments.

Maximum total sugar was reported in treatment T₁₄ (26.32%) during nine months storage period. Similarly maximum total sugar was reported in P₄ packaging material (20.97%) which was significantly higher over rest of the packaging materials. The interaction effects were also found to be significant.

Increase in reducing and total sugar during storage could be attributed to more rapid hydrolysis of polysaccharides and their subsequent conversion to sugars. Similar results were reported by Dabhade and Khedkar (1980a, 1980b) in Amchur prepared from cv Totapuri and seedling mango.

Ascorbic acid: Highest ascorbic acid was recorded in T₆ (26.47 mg/100 g) at 9 months storage. Packaging material P₄ recorded highest ascorbic acid (19.62 mg/ 100 g) at 9 month storage. T₆P₄ recorded highest ascorbic acid (28.44 mg/100 g) at 9 months storage period. Lowest ascorbic acid was noticed in treatment T₁₄ and packaging material P₁. Interaction effects were non-significant during 9 months storage period.

The highest content of ascorbic acid in T₆P₄ could be due to the dipping of slices in higher concentration of preservative solution used at the time of blanching and dehydration in cabinet drier which might have prevented loss of ascorbic acid. Loss of ascorbic acid was rather rapid in sun-dried samples which could be attributed to exposure of raw mango slices to sunlight. Similar results have been reported by Dhabade and Khedkar (1980a, 1980b).

Starch: Maximum starch was observed in T₆ (23.54%) at 9 months storage and was significantly superior over all other treatments. With regards to packaging material highest starch content was noticed in P₄ (20.29%) in 9 months storage. Interaction effects were found to be significant. Treatment combination T₆P₄ (23.81%) recorded maximum starch content. The high starch in T₆P₄ could be due to dipping of slices in higher concentration of preservative solution and dehydration in cabinet drier which helped to reduce the loss of starch. Loss in content of starch was slightly more in sun-dried samples which could be attributed to the exposure of raw mango slices to sunlight. Decrease in starch could be ascribed to the hydrolysis of starch. Similar results were reported by Dhabade and Khedkar (1980a, 1980b) in Amchur prepared from cv Totapuri and seedling mango.

Beta-carotene: Maximum beta-carotene was noticed in T₆ (287 mg/100 g) at 9 months storage and packaging material P₄ (254 mg/100 g) and was significantly superior over all other treatments. Treatment combination T₆P₄ (291 mg/ 100 g) recorded highest beta-carotene. The highest content of beta-carotene could be due to the dipping of slices in the higher concentration of preservative solution and dehydration in drier which preserved the carotene. Loss of beta-carotene was more in sun-dried samples which could be due to exposure of raw slices to sunlight. The decrease in beta-carotene during storage may be due to temperature and light effect on pigments. Similar observations were reported by Vijayanand et al (2001) in mango chunks.

Moisture content of Amchur was found to be high in control whereas it was low in Amchur prepared by blanching slices for five minutes + five minutes dip in 0.5 per cent KMS + sun drying. Maximum TSS, ascorbic acid, starch and beta-carotene was observed in Amchur prepared by blanching slices for five minutes + five minutes dip in 1.5 per cent KMS + cabinet drying and lowest in Amchur prepared by no blanching + no KMS + cabinet drying (control) whereas lowest ascorbic acid, starch, beta-carotene were noticed in Amchur prepared without blanching + no KMS + sundrying (control). Acidity was found to be highest in Amchur prepared without blanching + no KMS + sun drying (control) and lowest was seen in Amchur prepared by blanching slices for 5 minutes + 5 minutes dip in 0.5 per cent KMS + sun drying. Reducing and total sugar was found to be maximum in Amchur prepared without blanching + no KMS + cabinet drying (control) and minimum in treatment comprising blanching slices for 5 minutes + 5 minutes dip in 0.5 per cent KMS + sun drying.

T₁ : Blanching slices for 5 min + 5 min dip in 0.5% KMS + sun drying, T₂: Blanching slices for 5 min + 5 min dip in 1.0% KMS + sun drying, T₃: Blanching slices for 5 min + 5 min dip in 1.5% KMS + sun drying, T₄: Blanching slices for 5 min + 5 min dip in 0.5% KMS + cabinet drying, T₅: Blanching slices for 5 min + 5 min dip in 1.0% KMS + cabinet drying, T₆: Blanching slices for 5 min + 5 min dip in 1.5% KMS + cabinet drying, T₇: Slices dip in 0.5% KMS for 5 min + sun drying (no blanching), T₈: Slices dip in 0.1% KMS for 5 min + sun drying (no blanching), T₉: Slices dip in 1.5% KMS for 5 min + sun drying (no blanching), T₁₀ : Slices dip in 0.5% KMS for 5 min + cabinet drying (no blanching), T₁₁ : Slices dip in 1.0% KMS for 5 min + cabinet drying(no blanching), T₁₂:Slices dip in 1.5% KMS for 5 min + cabinet drying, T₁₃:No blanching + no KMS + sun drying(control), T₁₄:No blanching + no KMS + sun drying(control), P₁: 100 gauage polyethylene, P₂: 300 gauage polyethylene, P₄: 400 gauage polyethylene.

References