An unexpected outcome of communicating science using food is that methods from the kitchen can impact research in our laboratory. In a recent undergraduate student project, students studied the mechanism of nitrous oxide to extract flavor from herbs. While nitrous oxide pressurization is commonly used for generating foams such as whipped cream, this method is also used to extract flavors from herbs[ 17 , 18 ]. The proposed mechanism for flavor extraction is mechanical disruption of cells upon pressure release, whereby the bubbles of nitrous oxide gas increase in size, and thereby disrupt cellular structures, such as lipid membranes[ 19 ].
Our preliminary results show that this method can also be used for subcellular fractionation and nuclear isolation protocols, where rupturing the plant cell wall is a prerequisite to liberating the internal contents of the cell.
Using nitrous oxide pressurization can potentially provide a faster and easier way to disrupt plant cells: in contrast to other protocols, this method could sidestep the need for enzymatic treatment, which can be costly and time-consuming. Based on preliminary student and audience feedback, communicating science using the tactile medium of food is an effective method to engage people in scientific inquiry.
Food can also captivate people to understand more about the molecular and scientific basis of the foods, cells and nuclei that we eat.
Given the increasing demand to promote knowledge of science and the origins of the foods that we eat, such dialogue on science and food is essential. Barham P: The science of cooking. Book Google Scholar. Jacobs H: The molecular biology of the hamburger.
EMBO Rep. J Chemical Education. Wolf LK: Kitchen chemistry classes take Off. Chem Eng News. Google Scholar. J Chem Education. Grosser AE: Cooking with chemistry. Article Google Scholar. Berenbaum MR: Bugs in the system: insects and their impact on human affairs. Huffington Post. Where do milk, eggs and bacon come from? The Telegraph. Spiegel JE: Introducing children to the sources of food.
The New York Times. Chocolate in Health and Nutrition. Food is any substance normally eaten or drunk by living things. The term food also includes liquid drinks. Food is the main source of energy and of nutrition for animals, and is usually of animal or plant origin.
There are 4 four basic food energy sources: fats, proteins, carbohydrates and alchol. Humans are omnivorous animals that can consume both plant and animal products.
We changed from gatherers to hunter gatherers. After the experience of the Ice Age it is probable that humans wanted to create some feeling of security by controlling what plants were growing and which animals were available. This led to agriculture, which has continually improved and altered the way in which food is obtained. In biochemistry, fat is a generic term for a class of lipids.
Fats are produced by organic processes in animals and plants. All fats are insoluble in water and have a density significantly below that of water i. Fats that are liquid at room temperature are often referred to as oil. Most fats are composed primarily of triglycerides; some monoglycerides and diglycerides are mixed in, produced by incomplete esterification.
These are extracted and used as an ingredient. Products with a lot of saturated fats tend to be solid at room temperature, while products containing unsaturated fats, which include monounsaturated fats and polyunsaturated fats, tend to be liquid at room temperature.
Predominantly saturated fats solid at room temperature include all animal fats e. All other vegetable fats, such as those coming from olive, peanut, maize corn oil , cottonseed, sunflower, safflower, and soybean, are predominantly unsaturated and remain liquid at room temperature. However, both vegetable and animal fats contain saturated and unsaturated fats.
Some oils such as olive oil contain in majority monounsaturated fats, while others present quite a high percentage of polyunsaturated fats sunflower, rape. A protein is a complex, high molecular weight organic compound that consists of amino acids joined by peptide bonds.
Interested in learning more of these fundamental concepts of food science? Atoms are the building blocks of molecules, each and everything in this world is build up of atoms. Different atom types will have different numbers of these building blocks, but they will contain the same type of building blocks. An important concept of these three building blocks is that they each have an electric charge.
The protons and neutron of an atom form the center nucleus of an atom, the negatively charger electrons float around this center at a slightly further distance.
Electrons are small compared to protons and neutrons. Since they float away from the nucleus these can tend to be exchanged between atoms more easily. They play an important role in chemical reactions, and when making molecules. There is a limited number of the elements or atom types in the world, only These are all grouped in the so-called period table of elements, of which you might have heard in chemistry lessons.
The simplest element has only one proton, every subsequent element has one additional proton, up to that Whereas electrons can be exchanged quite easily, that is not the case for the protons and neutrons. What better way to do so than through a song? The number of protons defines the element, so what do neutrons do?
The number of neutrons determines the isotope of an element. Since there are elements, chemists had to find a convenient way to name them. Using their full names all the time, would be confusing, especially when we start describing molecules, which are again build up of atoms.
Within food there is a relatively small number of common atoms. Four of them are especially common, carbon, oxygen, nitrogen and hydrogen. Molecules are larger structures of atoms which have reacted with one another to form a stable component. Most atoms are not stable by themselves, you will not find a pure oxygen atom in the air, instead, two oxygen atoms will have reacted to form one oxygen molecule O 2.
The same goes for hydrogen H 2. We use the abbreviations of atoms we just learned to indicate which of these atoms are all present in a molecule. Each molecule will be a different combination of these atoms. The atoms will be attached to each other in different ways and orders.
Molecules are represented by showing the letters of the atoms they are built from and using a small subscript number to indicate how many of this atom are present in the molecule as I did for the oxygen and hydrogen molecules. In a separate post we discuss these formulas in more detail. Instead, you also need to know how these atoms are attached to one another. The way the atoms are attached to each other greatly influences the way they will react. A meta-analysis of observational studies suggested an inverse association between soy food consumption and risk of type 2 diabetes, especially in women and Asians [ ].
This is in accordance with another study, which suggested that post-menopausal women who consumed a high soy diet had a lower fasting insulin, compared with those with no daily genistein consumption. Besides, women with high genistein intake had a significantly lower body mass index and waist circumference [ ]. Recently, another study has drawn a similar conclusion, that dietary soy intake is inversely associated with risk of type 2 diabetes in Japanese women, but not in men [ ].
Although many studies have investigated the benefit of soy isoflavone consumption of blood glucose, well-designed studies are needed to fully understand the underlying mechanisms and evaluate the exact effects of soy isoflavones on diabetes. In April , the American Diabetes Association ADA released a nutrition report with eating recommendations to help manage and prevent diabetes, and also to prevent complications such as heart disease. In this report, there are no amendments related to soy consumption for diabetic patients.
The only specific remark is for patients with diabetic kidney disease and macroalbuminuria, who can change to a more soy-based source of protein in order to improve the cardiovascular disease risk factors but proteinuria is not altered [ ]. The connection between soy consumption and bone health has emerged with epidemiologic studies, which found that Asian women have a lower hip fracture incidence in the elderly compared to Caucasian women.
Later, it was confirmed that consumption of soybean and soy-based products, much higher among Asians, could potentially lower the bone loss rate and decrease the risk of fracture [ ]. To date, the exact effects of dietary soy isoflavones on osteoporotic bone loss remain inconclusive, and results vary from study to study.
Most studies, performed in vitro or using animal models, have found an inverse relation between the consumption of soy isoflavones and the percentage of bone loss. As an example, genistein was shown to reduce biochemical markers of bone metabolism, to prevent trabecular bone loss, and affect thyroid follicular cells in a male rat model of osteoporosis [ ].
In humans, a post-hoc analysis of a multicenter randomized controlled trial suggested that genistein may be useful not only in postmenopausal osteopenia, but also in osteoporosis. Also, genistein has possible implications for the reduction of fracture risk in postmenopausal women with osteoporosis. These effects seem to be time-dependent and a long-term intake of genistein will produce ongoing effects on bone health [ ]. Specifically, genistein was found to retard bone resorption by decreasing the viability of 1,dihyroxyvitamin D-induced osteoclasts.
Other mechanisms implied enhanced bone formation by increasing serum osteocalcin concentration, femoral insulin-like growth factor 1 mRNA transcription, and serum alkaline phosphatase activity [ ].
However, clinical trials outcomes are still conflicting and more well-designed studies are warranted to delineate the underlying mechanisms, the efficacy, and safety of soy isoflavones in osteoporosis.
Perhaps due to these current uncertainties, the National Center for Complementary and Integrative Health NCCIH declared that soy isoflavone combinations do not lower the rate of bone loss in Western women during or after menopause [ ].
The use of soy-based foods or soy supplements in alleviating menopausal symptoms such as hot flashes, night sweats, and vaginal dryness has long been a controversial subject. A systematic review and meta-analysis published in has shown that individual phytoestrogen interventions such as dietary and supplemental soy isoflavones were associated with improvement in daily hot flashes and vaginal dryness score, but no significant reduction in night sweats.
However, the study concludes that further rigorous studies are needed to determine the exact association of plant-based and natural therapies with menopausal health [ ]. Also, a recent analysis concluded that frequent consumption of soy products e. In contrast, a Cochrane systematic review determined that there is no conclusive evidence that phytoestrogen supplements effectively reduce the frequency or severity of hot flushes and night sweats in perimenopausal or postmenopausal women.
Still, the study admits that genistein concentrates might pose beneficial effects, which should be further investigated [ ]. The North American Menopause Society report on the role of soy isoflavones in menopausal health has concluded that initial treatment with soy-based isoflavones is reasonable for stressful vasomotor symptoms in postmenopausal women. Supplements providing higher proportions of genistein or S Y -equol may provide more benefits. If a woman responds to isoflavone supplementation, treatment can continue with monitoring for side effects, but if a woman does not respond after 12 weeks, other treatment options should be discussed.
The report also emphasizes on the urge of larger clinical studies aimed to investigate the exact role and mechanisms of isoflavones in postmenopausal women [ ]. Polysaccharides are natural polymers, found in various plants, algae, animals, and microorganisms. These polymers have exceptional properties and essential roles to sustain life. They are an important class of polymeric molecules composed of long chains of monosaccharide units bound together by glycosidic linkages [ ]. General classification of polysaccharides is highly diverse; they are classified in different ways, based on their composition, function, and origin [ ].
Therefore, an overview of the main polysaccharides, including their potential food and medical applications, is presented in Table 2. Depending on the single sugar moieties glucose, galactose, fructose, mannose , polysaccharides are classified in two groups: 1 homo-polysaccharides , which contain only one kind of polymerized sugar unit like starch, xylan, galactan, and froctan, and 2 hetero-polysaccharides, containing two or more kinds of sugar units such as pectin [ ].
Polysaccharide-based substances are increasingly used in health and cosmetic products manufacturing, food and feed production, and for obtaining cellulose-derived materials [ ].
Recently, there has been an increased interest for polysaccharides use in various novel applications due to their biocompatibility, biodegradability, non-toxicity, and several specific therapeutic activities [ ].
The relationships between polysaccharides, the effects of processing on their structures and interactions, and their behavior in the gastrointestinal tract are crucial for elucidating the relationships between diet and health [ ]. Many foods contain a great number of polysaccharides that cannot be completely digested by the digestive system. These indigestible polysaccharides can be called dietary fibers [ ]. The class of polysaccharides such as pectin, inulin, and gums are able to slow the food movement in the digestive tract and to slow the sugar absorption from food into blood.
The specific action of polysaccharide at digestive tract is given by the fermentable process. Prebiotics are selectively fermented ingredients that result in specific changes of the gastrointestinal microbiota. They improve the mucosal barrier function of the intestine by reducing the expressions of pro-inflammatory cytokines [ ].
Therefore, regular consumption of polysaccharides is suggested to beneficially enhance the gut physiology and the metabolic balance by influencing metabolic functions [ ]. Intestinal microbiota degrades the polysaccharides to produce metabolites and many intestinal bacteria can use these polysaccharides as unique carbon sources during the fermentation process.
An in vitro study, which simulated the human colonic fermentation and used two types of indigestible polysaccharides apple pectin and inulin as energy sources to three different human bowel microorganisms, showed that the low degree of polymerized inulin positively modulated the intestinal microbiota and improved the flora diversity [ ].
Incidence of inflammatory bowel disease has increased considerably in recent years. Therefore, the development of a new adjuvant therapy strategy that may involve natural sources such as dietary modifications is a challenging task [ ]. The inflammatory symptoms were decreased after the oral administrations of a guar gum or partially hydrolyzed guar gum mixture, a pectin-type polysaccharide; also, the bowel movement, stool consistency, the abdominal pain and diarrhea were improved [ , ].
Current research shows that the immune-stimulating and immune-modulating functions [ , ] of polysaccharides; these polysaccharides are called bioactive polysaccharides, they can also stimulate the immune system against cancer cells by increasing immunoglobulin. The apple-derived pectin is one of the polysaccharides that have been reported to ameliorate metabolic syndrome, and it reduces body weight and the excessive accumulation of fat.
Also, the exopolysaccharides isolated from Kefir grains present the same effects as pectin. Studies have shown that moderate intakes of dietary fiber like polysaccharides can effectively lower risks for developing diabetes [ ].
The major effect of soluble non-starch polysaccharides in slowing glucose absorption is therefore of considerable benefit in terms of diabetes risk and management but also has implications for overall starch digestion [ ]. In recent decades, new exploitation of polysaccharides and their derivatives focused on tissue engineering applications, such as biological signaling, cell adhesion, cell proliferation, cell differentiation, and cell responsive degradation. In the initial processing stage, there are several factors that may trigger important modifications of polysaccharide properties.
A careful attention paid to these factors is essential in establishing the polysaccharides use in food and biomedical applications. Mechanical fractionation has action on crystalline structure of starch. Dehulling and milling of cereal grains and peeling and chopping of potatoes cause physical damage to a proportion of starch granules. However, this type of starch damaged possesses a water absorption capacity 10 times greater than native starch and it is more prone to gelatinization with implications for end-use properties and digestion [ , ].
High temperature accelerated the degradation of high-molecular weight polysaccharides to low-molecular weight oligosaccharides and monosaccharide. Thermal processes induce two different major reaction pathways, such as the Maillard reaction, which takes place in the presence of amino acids, and caramelization, that occurs when simple sugars are heated at high temperatures [ , ].
The predominant products of thermal decomposition of pure starch in toasted bread are the dehydrated oligomers of glucose and individual molecules of dehydrated glucose, which are involved in the Maillard reaction [ ]. However, in the case of starch, the thermal decomposition showed no significant relationship between microstructure crystallinity, granule size and the thermal degradation process [ , ].
It should be noted that many dietary products containing polysaccharides are processed by thermal treatment, and the chemical structure of the carbohydrates is dramatically altered by heat treatment [ , ]. The main effect of physical modification is to truncate the original polysaccharide backbone to get fragments with lower molecular weights and only cause some conformational changes.
Microwave exposure could degrade polysaccharide structure, and thus increase solubility and biological activity. Microwave heating is described as more homogeneous, selective, and efficient as compared to conventional heating, resulting in faster reactions with fewer or no side products. The polysaccharide degradation in a microwave oven is generated by the interaction between electromagnetic field and chemical constituents of polysaccharide, due to molecular vibration and intense friction [ ].
New applications of microwave heating were used in the grafting modifications of polysaccharides, with the precise control of the graft polymer. Microwave irradiation can be a method for the development of valuable products with tailor made properties [ ].
It has been shown that the properties of microwave-synthesized graft polysaccharides are normally superior to the derivatives synthesized conventionally, but it still requires very careful control of reaction parameters to obtain polysaccharides with suitable properties and grafting efficiency.
Microwave application has advantages of economical usage of time and power energy, and also, it is easy to operate [ , , ]. Another type of physical treatment is application of ultra-high pressure widely used in food and medicine. Depolymerization is the main effect caused by the application of high pressure treatment on polysaccharides; it was shown that the effect of high pressure was found to be dependent on the structure and conformation of the polysaccharides and strongly on their structure: globular branched structures similar to gum arabic are nearly unaffected, while linear stiff polymers undergo depolymerization [ , ].
Gum arabic was found not to be affected by the high pressure treatment, probably because of its branched and globular structures [ ]; the same effect was also identified on cellulose [ ]. Radiation processing of natural polymers has received much less attention over the years because most of the natural polymers undergo chain scission reaction when exposed to high-energy radiation and because of the difficulty in processing natural polymers in various forms and sizes [ ].
Regarding the effect of gamma irradiation on starch, the result showed increased water solubility and water absorption and, also, an increase of antioxidant activity [ ].
Besides new technologies based on polysaccharides, irradiation can be used for the decontamination of food and food additives as well as for the sterilization of materials containing polysaccharides. The irradiation of polysaccharide-containing systems has already found or has potential to find use in plastics technology, in nanotechnology, in medicinal and pharmaceutical areas, in the food industry, and in the chemical and other technical industries [ ]. Seafood products are considered inherently functional due to their many valuable compounds and bioactive molecules possessing health benefits [ , ].
Bioactive components can be isolated from seafoods and seafood co-products and further added to various foods to enhance their functionality in terms of human health [ ].
According to recent studies, biologically active protein and lipid compounds can be extracted from fish and other marine organisms like sponges, tunicates, sea hares and slugs, soft corals, bryozoans, as well as marine animals and seafood side streams. The bioactives with strong health-promoting effects include vitamins, fish muscle proteins, marine peptides and depsipeptides, collagen and gelatin, fish oil, PUFAs, etc. Some of these bioactive components are of particular pharmaceutical and nutraceutical interest due to claimed health benefits [ ].
A big part of marine bioactive compounds has been isolated, characterized, and further modified for the development of analogs with improved activities [ , , ]. Bioactive peptides extracted from marine organisms and seafood by-products have been reported to possess various activities, including antimicrobial, immunomodulatory, antithrombotic, antioxidant, mineral binding, hypocholesterolemic, and antihypertensive actions [ ].
Fish is a rich source of valuable protein and lipid components worldwide [ ]. Moreover, fish muscle proteins possess the potential of providing bioactive peptides to the food, pharmaceutical, and nutraceutical industries [ ]. Other marine sources for bioactive peptides include sponges, ascidians, tunicates, and mollusks. A number of these marine species have been studied in depth for presence of bioactive peptides and depsipeptides, including clinical assays, and an extensive group of bioactive peptides has been found [ ].
The reported group of bioactive peptides includes compounds with antitumor activities such as Aurilide from tunicate Dolabella auricularia [ ], Didemnin from tunicate Trididemnum sp. Antiproliferative bioactivities were found in Mollamide from ascidian Didemnum molle [ ] and other bioactive peptides such as Geodiamolide H, Phakellistatins, and Jaspamide isolated from sponges of the genus Geodia sp.
The most preferred method to extract bioactive peptides is enzymatic hydrolysis. Enzymatic hydrolysis results in several peptides with different bioactivities, which offers a huge potential to use them in pharmaceuticals and nutraceuticals.
The biological activity of small peptides present in protein hydrolysates depends on their molecular weight and amino acid sequences [ ]. A fractionation step is generally applied to crude hydrolysates to separate individual peptides by using different techniques, such as gel permeation chromatography or reverse-phase high-performance liquid chromatography RP-HPLC [ , ]. Bioactive peptides recovered by enzymatic hydrolysis are usually consisted of 2—20 amino acid residues, and their activities are influenced by their amino acid composition and sequence.
A high number of hydrolyzed proteins extracted from seafood by-products have been assayed for various bioactivities, such as antioxidant, antiproliferative, antitubulin, and cytotoxic activities [ ]. These biological activities can possess anticancer potential, providing the opportunity to use the recovered peptides in cancer therapy [ ].
As mentioned above, seafood side streams and co-products resulting after fish processing are rich sources of valuable protein ingredients for further exploitation in the production of new products such as feed, functional foods, cosmetics, and nutraceuticals [ ].
Various seafood rest raw materials such as heads, skin, cut-offs, frame, bone, and viscera can be utilized to isolate a number of bioactive protein ingredients [ ].
Fish rest raw material resulting after filleting contains high amounts of high-value proteins containing all essential amino acids. Enzymatic hydrolysis can be used to obtain fish protein hydrolysates FPH for further isolation of bioactive peptides. FPH have been shown to contain peptides with, for example, immunostimulating and blood pressure-lowering ACE-inhibiting properties, in addition to antiproliferative antimicrobial , anticoagulant, and immunomodulatory effects.
These peptides may be used in novel formulations of nutraceuticals and cosmeceuticals [ ].
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