Frequently Asked Questions

Table grapes (Vitis vinifera L.), are nonclimacteric fruits with a relatively low rate of physiological activity, are exposed to serious water loss after harvest, which result in stem drying and browning, berry shatter, and shrivelling. The maintenance of postharvest quality of table grape is becoming increasingly significant as the supply of high quality commodities constantly exceed demand. The consumer expectation in the supply of fresh produce is partly matched by long term storage.

Grapes are highly perishable commodities and thus length of storage is limited by certain factors such as fruit maturity at harvest, pre-cooling, storage conditions (temperature, relative humidity) and applications. Therefore studies focus on the improvement of better methods of handling, packing and many applications. The scientific basis for the application of various chemicals and methods to the storage of table grapes has been the subject of considerable research throughout the 20th and 21st centuries. Numerous chemicals have been examined to control Gray mould with a varying degree of success worldwide.

Studies reveal that optimum storage temperatures for most grape cultivars are between 30°and 32°F (-1° to 0°C). The relative humidity should be 90-95% RH and an air velocity of approximately 20-40 feet per minute (FPM) is suggested during storage to minimize moisture loss of berries and to maintain stems in good condition.

What are sulphur dioxide properties?
This is a gas that has properties that allow inhibiting the non enzymatic breakdown, the enzymatic activity, to control the development of microorganisms and act as an antioxidant.

What is the fresh guard emission mechanism?
Fresh guards have the ability to produce sulphur dioxide on a slow and also on a fast phase. The purpose of fast phase is to control immediately the fruit health and the slow phase during the process of grape conservation to avoid the disease advance.

What is the relative humidity importance on the fresh guard operation?
Stability on emission depends on the relative humidity. Condensation conditions due to heat alternation or delay on cooling, contribute to the emission of sulphur dioxide what means berries bleaching. The effects due to slow levels of relative humidity are being studied with the purpose to determine the critical points.

How does the sulphur dioxide fresh guard work?
As soon as the grape box is packed and humidity is produced inside it, the fast phase is activated producing a high SO2 gas concentration for a short time. Then, when the box is stored on cold conditions O° C (32F) the slow phase produces a low SO2 gas concentration for many weeks.

What`s the sulphur dioxide fresh guard function?
The fresh guard generates sulphur dioxide (SO2) gas as soon as the active ingredient (Na2S2O5) makes contact with the humidity. SO2 gas eliminates botrytis spores from grapes surfaces, seal wounds and cuts produced during the packing and stop the development of decay in grapes during the storage and transportation.

Is it important the temperature control?
The correct temperature control during the storage keeps a constant humidity level inside the boxes. This prevents a damage produced by bleached and the early grape guard exhausted. Botrytis spread twice at 2°C (35.6 °F) than at 0°C (32°F). The final grape condition depends on other factors like grape quality, packing or storage procedures, transport conditions, etc.

What’s the importance of cooling process?
Its objective is to keep the pulp temperature in around -0, 5 in order to inhibit the pathogen activity and to reduce processes associated to dehydration.

MAGMA POLYMERS PVT. LTD.

C-14, MIDC Area, Ambad, Nashik-422 010.

Phone : +91-2536600208 / 6601209

Email : freshguard@magmapolymers.in

              magmapolymerspvtltd@gmail.com

Disclaimer: Due to many factors that are outside of our control, we assume no liability for indirect or consequential damage relating to, or arising from the use of this product.Whether it is used in accordance to our suggestion or not.