ABSTRACTBurfi, an Indian milk‐based sweet, is susceptible to microbial spoilage that restricts its shelf life to 10 days. Large‐scale marketability of burfi and its export potential requires longer shelf life. Therefore, our aim was maximizing shelf life by packaging means. Studies were carried out on burfi in different packaging materials under different atmospheres – normal packing, vacuum packing and use of a free‐oxygen absorber – at 65% RH/27C. Normal packing even in barrier film did not effectively control microbial spoilage. Vacuum packing, although it retarded microbial growth, adversely affected texture and sensory quality. A free‐oxygen absorber coupled with high‐barrier materials like metallized films/foil laminates offered more than 45 days shelf life. Stored samples could be grouped by principal component analysis. The major sensory attributes contributing to grouping were color, firmness, chewiness, creamy and rancid notes. Sensory firmness and chewiness were found to have good correlation with instrumentally measured texture values.

Storage studies of almond milk powder mix of standard formulation comprising skimmed milk powder, cane sugar, starch, almond, cardamom and permitted food colour were conducted in 4 types of packages, viz., pouches made of polypropylene, polyester/polyethylene, metallized polyester/polyethylene and high-density polyethylene (H D PE) rigid containers. The storage conditions were 38degreesC with 92% RH and 27degreesC with 65% RH. The chemical, microbiological and sensory qualities of the product, initially and at regular intervals were assessed. The shelf-life of the mix was 20, 30, 65 and 90 days in polyester/polyethylene, polypropylene, metallised polyester/polyethylene and HDPE packaging materials, respectively at 38degreesC and 92% RH and could be stored for more than 6 months at 27degreesC and 65% RH in all the packages studied.

Moisture sorption studies were conducted on dry cereal products. viz..'Shabura' and 'Date' biscuits. Differences in moisture sorption properties were attributed to differences in the structure and sugar contents. The data obtained for texture and percent moisture were used in determining critical moisture levels. The mono-layer moisture contents corresponding to the Brunauer-Emmett-Teller (BET) and Guggenhem-Anderson-deBoer (GAB) were taken as the safe minimum moisture levels in the cereal products. The permissible water vapour transmission rate of the packaging material was computed, based on established initial and critical moisture levels.

Storage stability of chicken pickle in vinegar, packed in two types of pouches made from (i) metallized polyester/polyethylene and (ii) coextruded film of polyethylene/polyamide/ethylene-acrylic acid films has been studied for 90 and 180 days storage at (i) accelerated condition (38 degrees C with 90% RH), and (ii) normal or standard condition (27 degrees C with 65% RH). Except for a progressive increase in free fatty acid, and peroxide value, no significant changes (P>0.05) in other chemical parameters were observed. A decrease (P<0.05) in sensory quality occurred with storage. The product was found to be microbiologically safe. The experimental data indicated that both the types of pouches could be used to obtain shelf-life of 90 to 180 days under the conditions investigated.

The cyanobacteriumSpirulina platensis, produced at the Central Food Technological Research Institute, was dried using the cross-flow technique and subsequently subjected to packaging studies. The moisture sorption studies at 27 °C indicated a critical moisture content of 12.5%, corresponding to 56% relative humidity (RH). The product was packed in pouches made of polypropylene (37 μm thick) and a laminate of metallized polyester with low-density polyethylene and was stored at: (1) 38 °C, 90% RH (accelerated condition) or (2) 27 °C, 65% RH (standard condition). Periodically throughout its storage under these conditions, the product was analysed for its content of moisture, protein, ash and fat. In addition, determinations were made of the changes in the constituents carotene, phycocyanin and allophycocyanin.

The effect of addition of recycled and reused material on the physicochemical, extraction and migration properties of lowdensity polyethylene film was investigated. It was found that impact strength and barrier properties of recycled plastics were reduced greatly, while the extraction and migration values were enhanced. Addition of extrusion waste was found not to alter the properties significantly.

Moisture sorption isotherm of Kodbale, a popular Indian spicy savoury was found to be sigmoidal in shape; typical of a starchy food. The equilibrium moisture content at 56% RH was found to be 10.01% (dry basis), which was critical from the point of view of crispness and acceptability. The Brunnauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) - monolayer moisture content was 4.60%. The product packed in polyamide, based coextruded film and metallized polyester-polyethylene laminate with ambient air and nitrogen gas flushing indicated shelf-life of 60 to 80 days, when stored at 38-degrees-C and 90% RH. At 27-degrees-C and 65% RH storage condition, the shelf-life was about 120 days. Gas flushing and polyamide based material gave added protection against deteriorative changes.

Water vapour transmission rate values of co-extruded films having different webs and laminates at conditions of 38 +/- 1-degrees-C with 90 +/- 2% relative humidity and 27 +/- 1-degrees-C and 65 +/- 2% relative humidity indicated a linear relationship between RH and WVTR for low density polyethylene while hydrophilic polyamide containing composites indicated dependence on RH. The water vapour transmission rate of multi-layer films containing polyamide as the core layer ranged between 4.1 and 5.4 g/m2. day at 38 +/- 1-degrees-C and 90 +/- 2% relative humidity, while monofilms of polyolefins had values between 1.9 and 3.0 g/m2. day.

Brabender viscograms of rice flour from aged paddy (stored at room temperature, RT 20-degrees-33-degrees-C for 15 months) of two high amylose finegrain cultivars showed higher paste viscosities than that from the paddy stored at 4-degrees-6-degrees-C (cold) for the same period. The differences were almost elimated in case of isolated starches. The total amylose content was same for the starches from both aged (RT stored and cold stored) paddy. However, the hot water soluble amylose content was less in starches from "aged" paddy. The number average molecular weight (MBAR-n) as well as the swelling power and solubility of the starches from RT stored (aged) paddy were also less indicating that the aging of rice could partly be associated with the changes in the physicochemical properties of its starch.

A range of equilibrium moisture contents (EMC) of a blend of maize and pulse flours of 10.8% initial moisture content was produced by storing at 11-90% RH at 27 degree C. The critical EMC with respect to free flowing property and development of off-odour was 12.2%, corresponding to 65% RH. At 14.5% EMC (RH 75%) the product became soggy and developed stable odour; mould growth was evident beyond 86% RH. The flour blend was also filled in 1-kg pouches made of high density polyethylene woven material laminated to 150 gauge low density polyethylene liner and stored separately at (i) 27 degree C with 65% RH for 150 days and at (ii) 38 degree C with 90% RH for 50 days. Free fatty acids (FFA) and peroxide values (PV) were determined at regular intervals. In (i) the FFA (as % oleic acid) increased from 12.7 to 51.0 and PV (m-equiv. peroxide/kg fat) increased from 35.3 to 269.7 during 5 months storage; corresponding increases in (ii) were 12.7 to 41.7 and 35.3 to 125.1, resp., during 50 days storage. It was concluded that good shelf life can be expected in (i) up to 130 days and in (ii) up to 25 days of storage.