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The 2009 ASHS Annual Conference

Shelf Life Study of Blackberry Fruit In An Eco-Friendly Container

Saturday, July 25, 2009: 3:45 PM
Laclede (Millennium Hotel St. Louis)
MinJung Joo, Packaging, Michigan State University, East Lansing, MI
Hayati Samsudin, Packaging, Michigan State University, East Lansing, MI
Eva Almenar, Packaging, Michigan State University, East Lansing, MI
Rafael Auras, PhD, Packaging, Michigan State University, East Lansing
Janice Harte, Food science and Human Nutrition, Michigan State University, East Lansing, MI
Bruce Harte, School of Packaging, Michigan State University, East Lansing, MI
The postharvest life of blackberry fruit (Rubus ursinus) is relatively short due to its high respiration rate and its extremely fragile structure. These drawbacks can be counteracted by packaging and cold storage. Blackberry fruit is usually packaged in vented petroleum-based clamshell containers made of poly(ethylene terephthalate), PET, or poly(styrene), PS, and stored at roughly 32 °F to maintain quality and gain marketability and profitability during the postharvest period. Eco-friendly and non-vented corn-based containers made of poly(lactic acid) (PLA) may exceed the effectiveness of the aforementioned packages in prolonging blackberry shelf life by reducing the weight loss caused by the presence of vents while mitigating environmental problems related to packaging waste at the same time.
The aim of this study was to evaluate the shelf life of blackberries packaged in corn-based containers for approximately 3 weeks at 35oF (market conditions). Current petroleum-based clamshell containers were used as controls. Physical, chemical, microbiological and sensorial properties of berries from both types of containers were measured during storage. The PLA container reduced the weight loss of blackberries by 32% compared with that of the PET clamshell container. The absence of vents and the water vapor transmission rate of the PLA caused this difference. The firmness of blackberries packaged in PLA containers was maintained for roughly two days longer than for those fruit packaged in commercial clamshell containers. The sensory evaluation, a consumer preference test with more than 50 panelists, showed that panelists preferred appearance, texture, and flavor of the blackberries of PLA containers. Especially, texture and appearance showed a difference of more than 1 point between containers. Visual changes (dryness, fungal growth, …) were monitored during storage by using a digital camera. The study was carried out for two different varieties of blackberry grown in MI, Cancaska, and Chester, during different periods of time in summer 2008.
This study may help to generate background research since there is little attention on blackberry postharvest studies compared to other berries such as strawberries, and those are basically focused on blackberry nutritional benefits, mainly antioxidants content.