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In this work a study of critical storage temperatures on pigment degradation of green beans (Phaseolus vulgaris, cvs. Perona and Boby) was conducted. In this way, green beans kept better quality at 4 degrees C than either 8 or 12 degrees C, maintaining a bright green color and good texture. Nevertheless, temperatures of 4 degrees C induced chilling injury (CI) after eight days of storage, which became evident when the pods were transferred to 20 degrees C. Cold storage temperatures, 12, 8, and 4 degrees C, produced different changes on the green beans chlorophyll profile. Green beans of both cultivars, Perona and Boby, stored at 4 and 12 degrees C showed a continuous degradation of chlorophyll pigments during storage, while samples stored at 8 degrees C showed an increase of chlorophyll content at the first 15 days. Carotenoid pigments also suffered different changes during cold storage. Perona was the green beans cultivar which maintained the higher level of lutein, mainly when samples were stored at the most suitable temperature (8 degrees C).

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An HPLC study of the carotenoid composition of fresh, frozen and canned papaya fruit slices was done. There were no qualitative differences between the carotenoid patterns of fresh and frozen papaya fruit slices (cultivar Sunrise). The major carotenoids found in papaya extracts were lycopene and carotenol fatty acid esters of beta-cryptoxanthin and beta-cryptoxanthin-5, 6-epoxide. Other xanthophylls detected were beta-cryptoxanthin, trans-zeaxanthin and cryptoflavin. It was possible to determine the quantitative losses of carotenoids in papaya slices as a result of the freezing process and frozen storage, since samples of these fruits were available before processing. The pigment pattern of the canned product showed lycopene as being a major pigment. Thermal treatment induced the degradation of carotenol fatty acid esters of xanthophylls. The freezing and canning processing of papaya slices led to significant decreases in the total carotenoids quantified by HPLC, with frozen female slices and canned samples showing lower amounts of pigments. Hunter colour values of frozen slices were similar to those of fresh papaya fruit slices.

Controlled-atmosphere (CA) effects on chlorophyll and carotenoid concentrations in green beans were studied. Green bean pods (cv. Perona) were stored at 8 °C and 98% relative humidity, with and without controlled atmospheres (samples:  air, 5% O2−3% CO2; 3% O2−3% CO2; 1% O2−3% CO2), and then transferred to 20 °C to simulate ambient temperature. Green beans stored in air at 8 °C had good appearance for 18 days, whereas an atmosphere of 1% O2−3% CO2 extended the storage period to 22 days. Samples stored in other assayed atmospheres (5% O2−3% CO2 or 3% O2−3% CO2) had the same shelf life as the air-stored sample (18 days). Maximum chlorophyll accumulation in air-stored green beans took place at 6 days of storage, whereas the 1% O2−3% CO2 stored sample showed the maximum chlorophyll concentration at 13 days of storage, and no significant increase of this pigment was observed in the first 6 days. Degradation of chlorophylls a and b did not yield the corresponding pheophytin compounds, because the pheophytin content also showed a significant decrease during storage. Green bean carotenoids showed similar changes in chlorophyll concentrations during storage in air, 3% O2−3% CO2, and 5% O2−3% CO2. Keywords: Green beans; cold storage; controlled atmosphere; pigments; decay; shelf life