Saturday, January 9, 2010

Industrialization of food - complexities of strawberry storage

We live in ironic times, the selection of foods available has never been as diverse. You can walk into a supermarket and obtain "fresh" produce from the other side of the world, the range is huge from fresh dates to radishes, from lychees to pumpkins.

Because of the ability to source these "fresh" foods we don't see clinical deficiency diseases. 150 years ago in the middle of the industrial revolution due to the poor living conditions in cities having infants with scurvy was not uncommon.

So let us be grateful for the modern world we live in.

However the flip side is that our "fresh" food is no longer sourced locally and is in storage for a considerable length of time, thus our fresh produce is not really fresh at all. So even though we don't get scurvy we have a much reduced vitamin intake compared to if you grew your own food.

There is a lot of money to be made by making fruit and vegetables last longer. This enables the produce to be shipped further, kept on shelf longer and reduces wastage. Therefore there are lots of research projects around maximizing the life of fresh produce.

To give you an idea of how industrialized this process is, here is a case study on strawberry longevity.

Strawberries are picked before they are ripe, typically with a touch of white still on the end. This is because fully ripened strawberries go off very quickly and are more easily bruised. This also results in strawberries that need to be sweetened before eating as the natural process of sweetening is interrupted. Also the flesh is more white than natural ripened strawberries. This would imply a higher antioxidant level in the naturally ripened fruit.

Often strawberries go off due to grey mold growth (Rhizopus stolonifer) shown above. A very cool time lapse video shown here shows grey mold overtaking strawberries.

It turns out that treating the strawberries with a yeast (Rhodotorula glutinis) delays the mold onset. This yeast is rather distinctive for its bright pink or yellow colors (see picture to the right) 

Well new research shows that if you treat the yeast with chitin it is even longer before the grey mold takes over. Chitin is a carbohydrate, insect shells/exoskeletons along with shells of crabs are made of chitin. 

So in theory we pick strawberries before they are ripe then spray them with a yeast. This yeast has been grown up in solution containing insect shells (well chemically same chitin). Furthermore this type of process goes on with the "fresh" fruit and vegetables that we purchase. Any wonder that we are not getting enough nutrients in our diet. 


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