Walnut preservation requires special attention to impermeability and gas-tightness of the packaging. The VacQPack liner plays an important role in the preservation of walnuts, due to its Ethylene Vinyl Alcohol (EVOH) layer which protects the walnuts from oxygen and water vapor transmission.
Due to their high oil content, walnuts can quickly go rancid when in contact with oxygen.
Low pressure and a low level of oxygen will guarantee the best storage conditions, studies state (JUDY A. JOHNSON; 2000), because it tackles problems such as condensation, acidification, oxidation, and infestations.
Indianmeal moth (Plodia interpunctella), the most serious storage pest of dried fruits and nuts, was effectively controlled by all storage treatments, including a maintenance CA treatment of 5% oxygen (O2).
When an infestation is identified, like the Almond Moth, Ephestia cautella, or the Oryzaephilus Mercator, and the common nut weevil, VacQPack recommends the flush of CO2 as part of a correct MAP strategy.
CO2 applications are very effective against almond moth in quite short exposure times and can be regarded as an alternative to MeBr.
The flush of CO2 allied with vacuum and storage temperature (>75ºF) will perform a successful organic fumigation. Even eggs, normally the most dangerous element, because they can hatch long after the conventional fumigation, get eliminated.
The organoleptic characteristics of the walnut are preserved, packaged in palletized bulks, which make the handling and overall logistics less time and money consuming. Empirical experiences worldwide in the nut sector has been the way for VacQPack to improve its solution, making it ready to preform according to the parameters decided by the client.