Showing posts with label University of California. Show all posts
Showing posts with label University of California. Show all posts

May 30, 2014

Fresh vs. Frozen

In two recent studies from Britain, researchers purchased a half dozen different kinds of fruit and vegetables, all of which came in two varieties: fresh and frozen. After buying them and then having them chill out in either a fridge or freezer for three days, researchers conducted 40 tests to compare their nutritional content.

Turns out the frozen varieties were richer in health-boosting vitamins and antioxidants. In fact, frozen broccoli had four times more beta-carotene than its fresh counterpart, while frozen carrots had three times more lutein and double the beta-carotene as well as greater levels of vitamin C and polyphenols. Raspberries and peas performed about the same, whether they were fresh or frozen.

While it is true that foods gradually lose nutrients as they move through the supply chain, that chain is far longer for fresh produce. Fruits and vegetables are regularly held in storage for up to a month before you ever see them. Plus, according to study author Graham Bonwick Ph.D., a professor of applied biology at the University of Chester, once they hit your refrigerator  the nutritional loss escalates. It is probably due to the plant's continuing metabolic activity and how cells react to oxygen and exposure to artificial dark-light cycles.

A recent study from Rice University and the University of California at Davis found that the fluorescent lights of supermarkets and the constant darkness of your refrigerator affects fruit and vegetable circadian clocks so that they excrete fewer glucosinolates, compounds with cancer-fighting properties.

"Produce's degradation reactions are very much slowed by lowering the temperature to freezing levels," Bonwick says. "Furthermore, when you freeze produce, the water present in the cells of the food is locked up as ice, slowing or preventing these processes that require the presence of free water." Since produce in the freezer section was frozen solid almost immediately after being picked, it is preserved at its nutritional peak.

May 16, 2012

How Not to Spill Coffee

Rouslan Krechetnikov is a mechanical engineer at the University of California at Santa Barbara, and he spends most of his time working on fluid dynamics, the flow of air on a plane’s wings, the stability of a rocket, and other weighty problems. None of that has brought him as much attention as his newest paper in the journal Physical Review E: “Walking with coffee: Why does it spill?”

Krechetnikov and a graduate student, Hans Mayer, decided to divert from weightier subjects last year after a scientific conference, where they had watched fellow researchers stumble to their tables, trying not to get coffee all over themselves and the floor.

“The project was certainly fun. We just wanted to satisfy our curiosity and, given the results, to share what we learned with the scientific community through peer-reviewed literature,” Krechetnikov wrote.

They set up a simple experiment, watching a person walk in a straight line, mug in hand. They had their test subject look at the coffee cup. They had their test subject look at the floor ahead. They shot video of it all, recording how the coffee oscillated and how long it took to spill.

The results. Don’t rush. You may think the coffee will spill less if you get it to the table more quickly, but the opposite is true. Slow down and the sloshing will too. Watch the cup, not the floor. You will spill less.

The abstract concludes: “The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it.” Isn't science wonderful?