Food & Function Blog

Excess salt in the diet can lead to serious health conditions such as heart attack or stroke. Image © Shutterstock.

Salt (NaCl) is an important ingredient in many foods as it increases microbial stability, enhances flavour, and can influence the structure of macromolecules. However, consuming too much salt can lead to various health conditions such as hypertension (which can lead to a stroke or heart disease), and increase in calcium excretion (leading to osteoporosis and kidney stones). Manufacturers have attempted to create low sodium foods by substituting NaCl with other molecules such as potassium chloride (KCl), NaGlu or yeast extracts. However, in order to design palatable foods with lower salt contents it is necessary to understand the phenomena occurring during the oral processing of salt.

In this paper, Serafim Bakalis and co-workers from University of Birmingham, UK, have investigated salt release from food using a gustometer-type model system. The results show that if salt can be released in pulses, via controlled destructuring during oral processing, then tasty and healthier low salt foods can be developed. This is easier to achieve in solid foods such as bread and cheese where salt can be partitioned between different regions due to the slow diffusion kinetics. However, it is still a challenge for liquid and soft solid foods, as the interfaces have to be specifically tailored to ensure that partitioning is maintained over time.

Modelling the human response to saltiness, Benjamin J. D. Le Reverend, Ian T. Norton and Serafim Bakalis, Food Funct., 2013, DOI: 10.1039/c3fo30106k

Lipids are important compounds in foods and influence many factors from nutrition to mouth-feel. However, lipid compounds readily undergo oxidation reactions, which negatively effect the texture, odour and colour of foods, which in turn lead to a reduced shelf-life. In fact, some previous research has shown that oxidized lipids from the diet could directly contribute to major illnesses in humans, such as cancers and heart disease.

In order to prevent lipid oxidation, active packaging systems containing antioxidant agents, radical scavengers, metal chelators and ultraviolet (UV) absorbers have been introduced into the food industry with the aim to increase the safety and quality of packaged foods. Active packaging goes goes beyond the traditional role of packaging by imparting specific, intentional functionality to the packaging system and is discussed in depth in this recent Food & Function review. Here, Fang Tian, Eric Decker and Julie Goddard, from Massachusetts, USA, discuss the recent advances in antioxidant active packaging and highlight the development and application of active packaging systems. The opportunity to apply these antioxidant active packaging systems commercially is also discussed, with a focus on maintaining safety, quality and nutrition of packaged foods.

To find out more, click the link below to read the full article. It’s free until the 15th May:

Controlling lipid oxidation of food by active packaging technologies, Fang Tian, Eric A. Decker and Julie M. Goddard, Food Funct., 2013, DOI: 10.1039/c3fo30360h

Energy drinks could help enhance memory and attention. Image © Shutterstock’

Glucose is very important for healthy brain function as it modulates mental alertness and cognition. However, glucose cannot be easily stored and the brain requires a constant supply of glucose for fuel. Previous work has shown that consuming a glucose drink can enhance mental alertness, however the precise cognitive abilities that are susceptible to glucose remain unclear.

To investigate this further, Louise Brown and Leigh Riby from Nottingham Trent University and Northumbria University, UK, have examined the effects of glucose on episodic memory and attention processes. 35 participants performed an old/new recognition memory task and a Stroop colour naming task. The results showed that glucose enhances the neuro-cognitive processes related to verbal episodic memory and recollection, which was consistent with earlier work. However, there was also some evidence of enhanced attention during the task under difficult conditions. Therefore, the results suggest that glucose drinks may facilitate attention as well as memory.

To find out more, read the article in full by clicking the link below:

Glucose enhancement of event-related potentials associated with episodic memory and attention, Louise A. Brown and Leigh M. Riby, Food Funct., 2013, DOI: 10.1039/C3FO30243A

Omega-3 (w-3) fatty acids, found in foods such as oily fish, have previously been shown to reduce the risk of cardiovascular disease. However, studies on animals and humans have given conflicting results when it comes to the effects of w-3 on obesity. As obesity is associated with other conditions such as high cholesterol, inflammation and cardiovascular disease, reducing the body mass index (BMI) of obese patients (>30 kg m^¬2) to the normal range (20-25 kg m^¬2) is therefore important for good health.

In this research paper, Manohar Garg and Irene Munro from University of Newcastle, Australia, have investigated whether supplementation with LCw-3PUFA (omega-3 fatty acid) alone, then consumed in conjunction with a very low energy diet, facilitates weight loss. The team found that in their double blind randomised controlled trial, women are more responsive to the metabolism of LCw-3PUFA, which is possibly due to the hormone oestrogen and therefore they benefit from enhanced thermogenesis. However, due to the small number of male participants in this study, further research over a longer time period would be required to investigate gender differences and the potential link between LCw-3PUFA and BMI.

Read the full article for free until the 26th March 2013!

Prior supplementation with long chain omega-3 polyunsaturated fatty acids promotes weight loss in obese adults: a double-blinded randomised controlled trial, Irene A. Munro and Manohar L. Garg, Food Funct., 2013, DOI: 10.1039/c3fo60038f

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The texture and melting behaviour of chocolate are key factors for determining chocolate quality. Textural characteristics such as bite, firmness, melting properties, stickiness and smoothness are important, however, perhaps the most important factor is melting behaviour. It must be solid at room temperature (about 20 ºC) and melt at body temperature (37 ºC). When consumed it melts in the mouth, mixes with saliva and the phase inverts from a fat continuous product into an oil-in-water emulsion upon chewing. It is at this point that levels of mouth-coating can be perceived.

In this work, Bettina Wolf and co-workers from Nottingham, UK, have studied the microstructure of two chocolate samples following oral processing in order to understand the textural behaviour. Two milk chocolate samples with the same composition and viscosity in the melted state were manufactured differently to give differences in textural properties. The microstructureof the chocolate samples following oral processing resembled an emulsion as the chocolate phase inverts in-mouth and was clearly different and between the two samples. The sample that was found to be more mouth-coating appeared less flocculated after 20 chews. The team also performed tribological studies to measure friction properties. The research showed correlations between the sensory behaviour and the physical material properties relating to melting and friction behaviour.

To read the full article (free until the 13th February 2013) click the link below:

Oral processing of two milk chocolate samples, Ana Margarida Carvalho-da-Silva, Isabella Van Damme, Will Taylor, Joanne Hort and Bettina Wolf, Food Funct., 2013, DOI: 10.1039/c2fo30173c

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The consumption of excess saturated fat is known to increase the risk of obesity and cardiovascular disease. With this in mind, the food industry has been attempting to reduce the content of saturated and trans-fats in food products. In theory this could be achieved by replacing saturated fats, such as butter and hydrogenated oils, with unsaturated fats like vegetable oils. However, in practice, the physical characteristics of the food are altered and have less desirable qualities. Therefore, it is a challenge for scientists to reduce the saturated fat content of foods while maintaining the textural and mechanical properties such as mouth-feel, creaminess and firmness.

In this work, Alejandro Marangoni and co-workers from Guelph, Canada, have investigated the use of ethylcellulose (EC) oleogels for this purpose. Oleogels are very versatile and their mechanical properties can be tailored by altering the fatty acid profile of the oil component, or changing the viscosity or concentration of the polymer component. The team discovered that certain formulations of EC oleogels tend to separate into two distinct phases consisting of a soft interior core surrounded by a firm exterior sheath. The formation of the two distinct regions is highly dependent on the temperature gradient within the gel during setting. The results offer an alternative route to achieving a varying texture in an otherwise homogeneous gel.

Read this article for free until the 11th January 2013!

Fractionation of ethylcellulose oleogels during setting, Andrew J. Gravelle, Shai Barbut and Alejandro G. Marangoni, Food Funct., 2013, DOI: 10.1039/c2fo30227f

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Metabolic syndrome is a complex condition characterized by central obesity, atherogenic dyslipidemia, vascular dysfunction and insulin resistance. Visceral fat and oxidative stress are major factors contributing to developing metabolic syndrome. It is thought that the carotenoids lutein and zeaxanthin also play a pivotal role in this condition due to their antioxidant  activity and could offer protection against atherosclerosis and diabetes which are influenced by oxidative stress.

As eggs are a good source of highly bioavailable lutein and zeaxanthin (due to their incorporation in the lipid matrix of the yolk) scientists from Connecticut, US, have investigated the effects of eating 3 whole eggs daily for 12 weeks, as part of a weight loss regime. They found that, in combination with a carbohydrate restricted diet, eating eggs resulted in favorable effects on plasma carotenoid status in participants with metabolic syndrome. Furthermore, HDL and LDL were enriched with lutein and zeaxanthin, which may have significant health implications for preventing the development of metabolic syndrome-related conditions such as cardiovascular disease and type-2 diabetes.

To read the article in full for free until 3rd January 2013, please click the link below:

Egg intake improves carotenoid status by increasing plasma HDL cholesterol in adults with metabolic syndrome, Christopher N. Blesso, Catherine J. Andersen, Bradley W. Bolling and Maria Luz Fernandez, Food Funct., 2013, DOI: 10.1039/c2fo30154g

You may also be interested in this article which is free to access…

Effects of eggs on plasma lipoproteins in healthy populations, Maria Luz Fernandez, Food Funct., 2010, 1, 156-160

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Scientists from Texas, US, have investigated the effects of limonoids on human breast cancer cells. Limonoids, found in lemons and other citrus fruits such as oranges and grapefruit, have been previously found to exhibit various health benefits such as antitumor , antiproliferative and anti-inflammatory properties. They have also been shown to prevent coronary heart disease. However, the mechanism behind their anticancer activity remains unclear.

Estrogen is known to affect breast cancer, and the presence estrogen receptors (ER) results in a better prognosis for the patient compared to ER-negative tumors. In this work, the team isolated and identified limonoids from lemon seeds and screened them for cytotoxicity against both ER-negative (MDA-MB-231) and ER-positive (MCF-7) breast cancer cells. Most of the limonoids showed antiaromatase activity, however anti-proliferative activity was significantly correlated with caspase-7 activation by limonoids.

The results show that citrus limonoids may have the potential to prevent estrogen-responsive breast cancer (MCF-7) via caspase-7 dependent pathways.

To read the article in full, please click the link below. Free to access until the 12th December 2012! 

Limonoids and their anti-proliferative and anti-aromatase properties in human breast cancer cells, Jinhee Kim, Guddadarangavvanahally K. Jayaprakasha and Bhimanagouda S. Patil, Food Funct., 2013, DOI: 10.1039/c2fo30209h

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Celiac disease is an autoimmune disease which results in an intolerance to gluten ingestion. Currently, the only treatment available for Celiac disease sufferers is to abide by a gluten-free diet, but this is often difficult as gluten is found in many food products which contain wheat, rye and barley. Therefore gluten-free breads and similar foods are becomming increasingly popular with Celiac sufferers, however the fibre content of these products is usually low. Now, researchers from Sao Paulo, Brazil, have investigated the effects of increasing levels of prebiotic inulin-type fructans (ITFs – soluble dietary fibers) on the sensory and nutritional quality of gluten-free bread.

The research team found that adding ITFs to the gluten-free bread provides additional structure and gas retention during baking, thus improving the bread quality by creating softer crumbs and an improved crust, which improve the sensory enjoyment. The in vitro and in vivo glycemic responses were also studied and it was found that addition of 12% ITF was sufficient to decrease the glycemic response of gluten-free bread. This results in breads with a low glycemic index that are high in prebiotic dietary fibre and can benefit patients with either celiac disease or diabetes.

Read the full article for free until the 15th November 2012:

Effects of prebiotic inulin-type fructans on structure, quality, sensory acceptance and glycemic response of gluten-free breads, V. D. Capriles and J. A. G. Areas, Food Funct., 2012, DOI: 10.1039/c2fo10283h

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