The effect of chitosan on respiration, ethylene production, and quality attributes of tomato (Lycopersicon esculentum Mill.) fruit stored at 20C was investigated. Coating the fruit with chitosan solutions reduced the respiration rate and ethylene production, with greater effect at 2% than 1% chitosan. Coating increased the internal CO, and decreased the internal O2 levels of the tomatoes. Chitosan-coated tomatoes were firmer, higher in titratable acidity, less decayed, and exhibited less red pigmentation than the control fruit at the end of storage. Chemical name used: 2-amino-2- deoxy-p-D)-glucan (chitosan).

Ripe banana, cut to 10 mm thick slabs were osmotically treated in sugar solutions of 35, 50 and 65Њ Brix for 36 h. The initial moisture content fell from a value of 3.13 kg H 2 O DM to 2.19, 1.63 and 1.16 kg H 2 O kg Ϫ1 for treatment in the three solutions, respectively. These slabs, with Total Soluble Solids (TSS) contents of 26, 34 and 39Њ Brix, respectively, as well as freshly cut but untreated slabs (15Њ Brix) were air dried in a cabinet type tray drier to near equilibrium conditions at fixed temperatures from 40 to 80ЊC and at a constant air speed of 0.62 m s Ϫ1 . Drying was found to occur in the falling rate period only for both banana types and two drying constants K 1 and K 2 were established for a first and second falling rate period of drying. Increasing the drying air temperature significantly enhanced the drying rate and the K-values, except at 80ЊC when the rates fell, possibly because of case hardening of the slabs. Reducing the slab thickness also improved the drying rate, but increasing the air speed to 1.03 m s Ϫ1 did not have any profound effect. As the sugar content of the banana slabs increased through the osmotic treatment, drying rates fell. Calculated apparent moisture diffusivities at 60ЊC ranged from 34.8 ϫ 10 Ϫ10 m 2 s Ϫ1 (fresh slab) to 8.8 ϫ 10 Ϫ10 m 2 s Ϫ1 for dried (39Њ Brix) slabs. The moisture diffusivity was significantly lowered as the moisture content dropped in drying and with increased levels of sugar. Previously osmosed and then air dried banana slabs showed appealing colour and texture compared to the fresh banana.

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We investigated the effect of pre-storage exposure to shortwave ultra-violet (UV-C) light on the decay and quality of fresh strawberries. Fresh strawberries (cv. Kent, 25% to 50% red) were exposed to UV-C at doses of 0.25 and 1.0 kJ/m 2 and stored at 4 °C or 13 °C. UV treatment controlled the decay caused by Botrytis cinerea at both temperatures and extended the shelf-life of the fruits by 4 to 5 d. UV-treated fruits had a lower respiration rate, higher titratable acidity and anthocyanin content, and were firmer than the untreated fruits. The percentage of free sugars increased faster in UVtreated fruits at the beginning of the storage period. A lower electrical conductivity in fruits treated with 0.25 kJ/m 2 suggests a slower rate of senescence compared to the control. A higher electrical conductivity observed with 1.0 kJ/ m 2 suggests damage to the fruits. Overall, UV treatment at 0.25 kJ/m 2 appears to slow down the ripening and senescence of strawberry fruits stored at 4 °C.

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The cryoprotective effects of lactitol dihydrate, Polydextrose@ and Palatinit (Isomalt) at 8% w/w in cod-surimi were compared to an industrial control containing a sucrose/sorbitol 1:l mixture and a control without additive. Surimi was stored at -20°C for 12 wk and examined for freeze-induced protein changes every 2 wk by salt extractable protein and differential scanning calorimetry analyses: Palatinit@, lactitol and Polydextrose@ stabilized surimi proteins equally well as did the sucrose/sorbitol mixture. Salt extractable protein and myosin peak enthalpy for surimi were maintained at the same level as the industrial control. Confirming earlier results, initial T,,-myosin yielded information regarding surimi protein stability over extended periods of frozen storage.

Freeze-induced protein denaturation of cod surimi was studied as affected by carbohydrates (sucrose and glucose syrup at 8% w/w), polyols, (sorbitol and glycerol at 8% w/w), protein hydrolysatcs (fish protein and casein hydrolysates at 4% w/w), hydrocolloids (pectin-1% w/w, sodium alginate, lambda-and iota-carrageenan-0.5% w/w) and combinations of the above, (sucroseisorbitol 1:l mixture at 8% w/w, or combined with protein hydrolysates at 4% w/w). Salt cxtractable protein (SEP) and heat induced denaturation by differential by differential scanning caIorimetry (DSC) were used to monitor protein changes in surimi stored 16 wk at -20°C. The best clyoprotcction effect was achieved from sorbitol, glucose syrup (DE=GO), sucrose and sucrose/sorbitol 1:l w/w mixture at 8% w/w in surimi. Correlations between certain DSC parameters and SEP were high.