Effect OF Mois ture and Packaging on the She l f L i fe o f Wheat F lour

Tempering of the wheat samples with d ifferent amounts of water was done to obtain f lour t rea tments having different moisture levels i .e . T1 (13.5%), T2 (13%), T3 (12%), T4 (11%), T5 (10%) and T6 (9%) af ter mil l ing. These treatments were separately packed in polypropylene and paper bags. During the s torage per iod of 60 days, each t reatment in both polypropylene and paper bags was evaluated for proximate composi t ion, insect infestat ion, mold growth and to tal i ron. The crude protein and crude fa t decreased with s torage per iod. Mois ture content (m.c) in T1 (13.5% m.c.) , T2 (13% m.c. ) and T3 (12% m.c.) decreased. Changes were minimum in T4 (11% m.c.) and increasing trend was seen in T5 (10% m.c.) and T6 (9% m.c.) . The changes were more in polypropylene than in paper bags. Changes in ash and f iber were non s ignif icant dur ing the s tudy. Insect infestat ion and mould growth were also favored by higher mois ture content of f lour . Paper packaging was found to be sui table against insect infestat ion and mould growth. Total i ron also showed a decreasing t rend with s torage per iod. Lower f lour mois ture (T6= 9%) and paper packaging were found to be sui table for s torage s tabi l i ty & longer shelf l i fe of wheat f lour . ______________________________________________________________ INTRODUCTION In Pakis tan, wheat is mainly mil led to whole wheat f lour for the product ion of unleavened f lat bread local ly known as “Chapat i” while rest is used for o ther bakery products l ike bread, b iscui ts , cakes, pastr ies , pizzas etc . The annual product ion of wheat in Pakistan is 19.23 mil l ion tones and the area covered is 8 .69 mil l ion hectares (Anon. 2003). Mois ture content of f lour is very important regarding i ts shelf l i fe , lower the f lour mois ture , the bet ter i ts s torage s tabi l i ty. The deter iorat ion of baking qual i ty is a lso less a t lower moisture content which can be credi ted to retarded respirat ion and act iv i ty of microorganisms (Staudt and Zeigler , 1973) Mois ture is an important factor in control l ing grain infestat ion. Insects that l ive on s tored grains and their products depend upon the mois ture supply. General ly , moisture content of 9% or lower restr ic ts infestat ion. Mois ture is a lso of great importance for the safe s torage of cereals and their products regarding microorganisms, par t icular ly cer tain species of fungi . At lower mois ture fungi wil l not grow but a t about 14% or s l ightly above, fungal growth takes p lace (Hoseney, 1994) . Higher l ipolyt ic and proteolyt ic act iv i t ies are related to h igher moisture content , which fur ther lead to loss in nutr ients (protein and fat) and product ion of more FFA resul t ing in infer ior sensory character is t ics . In modern age, food packaging has become very important because of protect ion of the product f rom contaminat ion by macro & microorganisms and their f i l th , prevent ion from loss or gain of moisture , shield ing the product f rom oxygen and to faci l i ta te handl ing (Bal l , 1960) . Good packaging actual ly serves two purposes, which are essent ia l ly technical and presentat ional . Technical aspects in packaging aim to extend the shelf l i fe of the food by bet ter protect ion from al l the hazards dur ing s torage. Presentat ional aspects are not concerned with shelf l i fe but such packaging increases sales by creat ing a