First Taste

An international team of scientists led by the University of Bristol, has uncovered the earliest direct evidence of humans processing plants for food found anywhere in the world.

Researchers at the Organic Geochemistry Unit in the University of Bristol’s School of Chemistry, working with colleagues at Sapienza, University of Rome and the Universities of Modena and Milan, studied unglazed pottery dating from more than 10,000 years ago, from two sites in the Libyan Sahara.

The invention of cooking has long been recognised as a critical step in human development.

Ancient cooking would have initially involved the use of fires or pits and the invention of ceramic cooking vessels led to an expansion of food preparation techniques.

Cooking would have allowed the consumption of previously unpalatable or even toxic foodstuffs and would also have increased the availability of new energy sources.

Remarkably until now, evidence of cooking plants in early prehistoric cooking vessels has been lacking.

The researchers detected lipid residues of foodstuffs preserved within the fabric of unglazed cooking pots.

Significantly, over half of the vessels studied were found to have been used for processing plants based on the identification of diagnostic plant oil and wax compounds.

Detailed investigations of the molecular and stable isotope compositions showed a broad range of plants were processed, including grains, the leafy parts of terrestrial plants, and most unusually, aquatic plants.

The interpretations of the chemical signatures obtained from the pottery are supported by abundant plant remains preserved in remarkable condition due to the arid desert environment at the sites.

The plant chemical signatures from the pottery show that the processing of plants was practiced for over 4,000 years, indicating the importance of plants to the ancient people of the prehistoric Sahara.

Dr Julie Dunne, a post-doctoral research associate at Bristol’s School of Chemistry and lead author of the paper, said: “Until now, the importance of plants in prehistoric diets has been under-recognised but this work clearly demonstrates the importance of plants as a reliable dietary resource.

“These findings also emphasise the sophistication of these early hunter-gatherers in their utilisation of a broad range of plant types, and the ability to boil them for long periods of time in newly invented ceramic vessels would have significantly increased the range of plants prehistoric people could eat.”

Co-author Professor Richard Evershed, also from Bristol’s School of Chemistry, added: “The finding of extensive plant wax and oil residues in early prehistoric pottery provides us with an entirely different picture of the way early pottery was used in the Sahara compared to other regions in the ancient world.

“Our new evidence fits beautifully with the theories proposing very different patterns of plant and animal domestication in Africa and Europe/Eurasia.”

The research was funded by the UK’s Natural Environment Research Council (NERC) and is published in Nature Plants.

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Fresh Or Frozen

That Is The Question.

There’s a common belief fresh is best and buying frozen vegies is a cop out.
But certainly on the nutrition front, frozen veg aren’t necessarily inferior, says Melanie McGrice, a spokesperson for the Dietitians Association of Australia.
“Whether fresh is better than frozen, depends on how fresh the vegies actually are,” Ms McGrice said.
“Picking vegies from your own vegie garden out the back has to be the optimal situation. But vegies often have to travel a very long distance to get to us. This can take several days.
“We know that the longer it takes to get fresh food to us from the farm, the more the nutrients in the food slowly decrease.”
On the other hand, the nutrients in frozen produce are sealed into the veg during the freezing process.
One recent British study found antioxidant levels in frozen produce can actually be higher than in fresh fruit and vegetables.
This was “quite surprising”, because people have always thought antioxidant levels would be higher in fresh vegies, Ms McGrice said.
But two independent studies, which together included more than 40 tests on the most commonly bought fruit and vegetables showed in two thirds of cases, frozen foods had higher levels of antioxidant-type compounds, including vitamin C, polyphenols, anthocyanins, lutein and beta carotene on day three of storage.
It’s the water-soluble vitamins including vitamin C and some of the B vitamins that tend to be lost from our fresh produce the longer the vegies hang around, Ms McGrice said.
Vegetables are usually snap frozen very soon after they are picked. Special machinery is used to get the produce to -18 degrees Celsius in minutes.
The nutrients are ‘frozen in’ during this process, meaning you can quite easily have more vitamins in a frozen vegetable than in its ‘fresh’ counterpart.
But there is more to fruit and vegies than just vitamins.
One of the biggest reasons health experts want us to eat fruit and vegies is to get dietary fibre.
The good news is the fibre content doesn’t deteriorate easily, which means week-old fresh vegies still have value despite lowered vitamin levels.
So if it’s a choice of eating old vegetables or no vegies at all, old vegies are fine.
“And freezing doesn’t affect the fibre content of veg,” Ms McGrice adds.
Preparation is key.
How you cook your vegies is far more important than whether they are fresh or frozen.
“Boiling vegies in a large amount of water for a long time lets the vitamins leach out into the water,” Ms McGrice says.
Regardless of whether you are cooking fresh or frozen vegies, use as little water as you can and cook them for a short time. Steaming or microwaving vegies are much better options than boiling.
And if you are using frozen veg, Ms McGrice suggests checking the label of the packet.
“Usually they just contain the vegetable, but sometimes, particularly if there is a sauce, they may contain added salt and sugar,” she says.
(This can be a particular issue if you’re using canned vegetables, which are much more likely to include added salt.)
Here are some points to consider when you’re weighing up the pros and cons of fresh over frozen veg.

Fresh veg.
Can taste better than frozen.
Usually have a better texture.
If you’ve picked them straight from the garden, they will be bursting with nutrients.
But produce can be more than a week old by the time we eat it.
Frozen veg.
Nutrients are ‘frozen in’ soon after picking.
Convenience (can store for months)
Allows us to have vegies and fruit that are out of season
Adds variety to our diet.
After defrosting, vegies can have a soggy texture, because ice crystals damage the vegetable cell walls.

 

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Red Hot Chili Peppers

As a rock band, they may or may not suit your taste, but researchers at the Larner College of Medicine at the University of Vermont, have found that consumption of hot red chili peppers is associated with a 13 percent reduction in total mortality, primarily in deaths due to heart disease or stroke, in a large prospective study.

The study was published in PLoS ONE.

Going back for centuries, peppers and spices have been thought to be beneficial in the treatment of diseases, but only one other study conducted in China and published in 2015, has previously examined chili pepper consumption and its association with mortality. This new study corroborates the earlier study’s findings.

Using National Health and Nutritional Examination Survey (NHANES) III data collected from more than 16,000 Americans who were followed for up to 23 years, medical student Mustafa Chopan and Professor of Medicine Benjamin Littenberg, M.D., examined the baseline characteristics of the participants according to hot red chili pepper consumption. They found that consumers of hot red chili peppers tended to be “younger, male, white, Mexican-American, married, and to smoke cigarettes, drink alcohol, and consume more vegetables and meats, had lower HDL-cholesterol, lower income, and less education,” in comparison to participants who did not consume red chili peppers. They examined data from a median follow-up of 18.9 years and observed the number of deaths and then analysed specific causes of death.

“Although the mechanism by which peppers could delay mortality is far from certain, Transient Receptor Potential (TRP) channels, which are primary receptors for pungent agents such as capsaicin (the principal component in chili peppers), may in part be responsible for the observed relationship,” say the study authors.

There are some possible explanations for red chili peppers’ health benefits, state Chopan and Littenberg in the study. Among them are the fact that capsaicin is believed to play a role in cellular and molecular mechanisms that prevent obesity and modulate coronary blood flow, and also possesses antimicrobial properties that “may indirectly affect the host by altering the gut microbiota.”

“Because our study adds to the generalisability of previous findings, chili pepper or even spicy food consumption, may become a dietary recommendation and/or fuel further research in the form of clinical trials,” says Chopan.

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Brazzein

Low and no-calorie alternatives have become popular, as high-fructose corn syrup and sugar are on the outs with calorie-wary consumers. Soon, there could be another option that tastes more sugar-like than other substitutes. Scientists report in ACS’ Journal of Agricultural and Food Chemistry a step toward commercial production of a fruit protein called brazzein that is far sweeter than sugar and has fewer calories.

Brazzein first attracted attention as a potential sugar substitute years ago. Making it in large amounts however, has been challenging. Purifying it from the West African fruit that produces it naturally, would be difficult on a commercial scale and efforts to engineer microorganisms to make the protein have so far yielded a not-so-sweet version in low quantities. Kwang-Hoon Kong and colleagues are working on a new approach using yeast to churn out brazzein.

Working with Kluyveromyces lactis, the researchers coaxed the yeast to overproduce two proteins that are essential for assembling brazzein. By doing so, the team made 2.6 times more brazzein than they had before with the same organism. A panel of tasters found that the protein produced by this approach was more than 2,000 times sweeter than sugar.


 

Bourbon And Rye

Set “Em Up Joe.

Whiskey aficionados hold that Manhattans must be made with a fiery, grassy rye, while an Old Fashioned requires the sweetness of bourbon.

But a new study from a Drexel University food scientist shows the average consumer cannot discriminate between the two flavours.

Jacob Lahne, PhD, an assistant professor in the Center for Hospitality and Sport Management, found in a blind sorting task of American ryes and bourbons, participants were more likely to group together products by brand rather than type of whiskey.

The results were published in the Journal of Food Science.

“There is definitely a tendency for bartenders to talk about how some drinks should absolutely be made with bourbon or rye and I think it’s clear now that there is more flexibility,” Lahne said. “In a way it’s fun and exciting, it gives you a bigger universe to play with.”

The only legal difference between bourbon and rye products is their mashbill: Bourbon must be fermented from a mash that is majority corn, and rye from a majority of its eponymous grain. Otherwise, the legal and stylistic requirements for the two products are identical. So it’s possible for a 2 percent difference in mashbill to tip a whiskey from one category into the other.

Yet, in both pop culture and whiskey educator circles, the two kinds are held to be distinct, bourbon is often described like smooth caramel, while rye is called dry and brash.

Despite the quickly growing demand for whiskey in the United States (with revenues over $2.6 billion in 2014), there had been no rigorous examination of the assumed difference between bourbon and rye.

Lahne wanted to know, how can straight rye and bourbon be so dramatically different, if their basic recipe is so similar?

To get to the bottom of the conundrum, Lahne presented 21 study participants with trays of 10 anonymised whiskeys, five bourbons and five ryes, in random order. They were instructed to smell but not taste the alcohol. This method is in accordance with published guidelines for Scotch whisky evaluation.

The participants were then asked to organise the whiskeys into no fewer than two and no more than nine groups, by any criteria they wished. In a second session, when the participants came back days later, the same whiskeys were presented in an identical fashion with new, randomised labels. They were asked to sort the whiskeys into groups again.

The researchers next used a statistical analysis (called DISTATIS) to interpret the group’s responses. Lahne and his team found that the subjects did not separate the whiskeys based on mashbill (bourbon vs. rye), but instead were more influenced by properties like alcohol content, age at bottling and brand. For instance, participants were very likely to group together Jim Beam whiskeys.

Lahne hypothesises that the researchers saw this trend because individual makers have strong “house” flavours. Jim Beam whiskeys, both bourbons and ryes, might be characterised as smelling like roasted peanuts.

“It is interesting how distinctive that flavour is,” he said.

The perceived differences between bourbon and rye may stem from a time in history when mashbill differences between the two were greater, Lahne said. However, modern American whiskeys that are most popular today are very likely more closely related.

In future studies, Lahne and his team plan to further explore how specific sensory attributes like that peanut aroma, may be linked to producer, alcohol by volume, age, chemical makeup, and other production variables.


 

Red Signals Go

Colour helps us decide whether or not to eat something, according to a study at the International School for Advanced Studies (SISSA) in Trieste and published in the journal Scientific Reports stating that vision is the main sense we use to guide us in food choices. To evaluate calorie intake, we rely on a “colour code.”

“According to some theories, our visual system evolved to easily identify particularly nutritious berries, fruits and vegetables from jungle foliage,” says Raffaella Rumiati, SISSA neuroscientist and coordinator of the new study. The human visual system is trichromatic: in the retina, the light-sensitive organ of the eye, there are three classes of photoreceptors (cones) tuned preferentially to three different bands of the visible spectrum. This implies that we can see a large number of colours (more than monochromatic and dichromatic animals, less than those with 4, even 5 types of photoreceptor). “We are particularly efficient at distinguishing red from green,” says Rumiati. This sophistication testifies to the fact that we are “visual animals,” unlike others, dogs, for example, who depend on their sense of smell. “It is mainly the colour of food that guides us and our experiments show how,” explains Rumiati. “To date, only a few studies have been focused on the topic.”

What do we look for in food? Nutrition of course, or calorie-dense content and high protein. “In natural foods, colour is a good predictor of calories,” explains Francesco Foroni, SISSA researcher and first author of the study. “The redder an unprocessed food is, the more likely it is to be nutritious, while green foods tend to be low in calories.” Our visual system is clearly adapted to this regularity. “The participants in our experiments judged foods whose colour tended towards red as higher in calories, while the opposite was true for greens,” continues Giulio Pergola, a researcher at the University of Bari, and one of the authors of the study. “This is also true for processed, or cooked foods, where colour loses its effectiveness as an indicator of calories.”

Actually, the scientific literature shows clearly that cooked foods are favoured over natural foods and the phenomenon has been observed even in other species besides humans. “Cooked foods are always preferred because, compared to natural foods, there is more nutrition for the same quantity,” explains Rumiati. “With cooked foods however, the dominance of red over green no longer provides reliable information, which might lead us to believe that the brain would not apply the rule to processed foods. On the contrary, it does, which hints at the presence of ancient evolutionary mechanisms from before the introduction of cooking.”

Another nod in favour of this hypothesis is the fact that the colour code in the Rumiati and colleagues experiments does not come into play for items other than food: “The preference for red over green is not observed with non-edible objects,” says Rumiati. “This means that the colour code of the visual system activates correctly only with food stimuli.”

Our findings, besides increasing our knowledge of the visual system, offer interesting possibilities on many fronts which could have an important impact on the public health: marketing food, for example, and treating eating disorders. “Much is being done today to encourage healthier eating,” notes Rumiati. “For example, trying to convince the people to eat foods lower in calories.” Some countries propose bans on certain types of products, such as carbonated soft drinks and high fat foods. In some cases, there is a disclaimer on the packaging, as with cigarettes. Perhaps food colour could be used to produce significant results, even if artificial. ”


 

Age Difference

 

Simple changes in how we cook could go a long way towards preventing diabetes, say researchers at the Icahn School of Medicine at Mount Sinai. A new randomized controlled trial, published online in the journal Diabetologia, found that obese individuals with signs of insulin resistance showed improvement simply by avoiding the intake of advanced glycation endproducts, or AGEs, a byproduct of cooking found most commonly in dry heat-cooked or heat-processed foods.

 

The study is a follow-up to a 2014 article published in the journal Proceedings of the National Academy of Sciences. In the earlier study, the researchers, led by Helen Vlassara, MD, Professor Emeritus of Geriatrics and Palliative Medicine and Medicine at the Icahn School of Medicine at Mount Sinai, confirmed that high levels of AGEs in the body can cause pre-diabetes characterized by increasing insulin resistance, as well as brain changes similar to Alzheimer’s disease. This study focused more on diabetes risk.

 

“While food AGEs are prevalent, particularly in Western diets, our study showed that avoiding foods high in AGEs could actually reverse the damage that had been done,” said Dr. Vlassara. “This can provide us with new clinical approaches to pre-diabetes, potentially helping protect certain at-risk individuals from developing full diabetes and its devastating consequences.”

 

The researchers divided the study participants into two groups of obese individuals; one eating a regular diet, which is typically high in AGEs (Reg-AGE), and one with a diet low in AGEs (L-AGE). Members of the L-AGE group were instructed to avoid grilling, frying, or baking their food, in favor of poaching, stewing, or steaming.

 

At the beginning and end of the trial, blood and urine samples were analyzed to determine insulin resistance. The two groups showed similar levels of insulin resistance at the beginning; at the end, the L-AGE group showed significantly improved insulin resistance, as well as slightly decreased body weight and lowered levels of AGEs in the body. The Reg-AGE group had higher levels of AGEs and more markers of insulin resistance than during the baseline measurements.

 

“Elevated serum AGEs in individuals can be used as a marker to diagnose and treat ‘at risk’ obesity in patients,” said Jaime Uribarri, MD, Professor of Medicine (Nephrology) at the Icahn School of Medicine at Mount Sinai, another investigator in the study. “Even without losing a significant amount of weight, a reduced AGE diet can help prevent diabetes in these patients.”

 

The researchers also found a positive effect on six key genes associated with the regulation of oxidant stress and inflammation. Four of these had been found to be suppressed at the baseline blood and urine analysis, but were markedly increased at the end, including anti-inflammatory SIRT1 and adiponectin, as well as the receptor for the removal of AGEs, AGER1, and glyoxalase-1.