Summary Changes in the volatile aroma compounds of pineapple (Ananas comosus) during freezing and thawing were compared against fresh samples to determine the effect of freezing on pineapple flavour. An HS‐SPME–GC–MS analysis showed that the Smooth Cayenne pineapple variety had nineteen volatile compounds, in four classes of compounds including fourteen esters, two hydrocarbons, two sulphur‐containing compounds and one lactone. The main characteristic volatile compounds of the fresh pineapple were methyl hexanoate, ethyl hexanoate, ethyl 3‐methylthiopropanoate and 1‐(E,Z)‐3,5‐undecatriene. Freeze–thaw cycles were associated with the loss of some volatile aroma compounds, particularly the esters which were found to be the main characteristic of fresh pineapples. The freezing and thawing process was found to cause damage to the pineapple tissues due to ice recrystallisation and dehydration which lead to the reduction of volatile aroma compounds.

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Thermoplastic starch (TPS) and TPS/wheat gluten composites were prepared using compression molding. The wheat gluten contents ranged from 0 wt% to 20 wt%. The morphology of the fractured surfaces, thermal decomposition temperatures and mechanical properties of the TPS and TPS/wheat gluten composites were investigated using scanning election microscopy (SEM), thermal gravimetric analysis (TGA) and tensile testing, respectively. The maximum tensile strength of TPS/wheat gluten composites (1.1 MPa) was obtained when 10 wt% of wheat gluten was used. The crosslinking between wheat gluten protein chains caused an increase in the tensile strength of the TPS/wheat gluten composites. The temperature at the maximum weight loss of the TPS/wheat gluten composites was higher than for TPS. Moreover, wheat gluten decreased the water absorption.

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