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The Science of Spirulina
INCREDIENTS - By Pia Mauates
( MEAT PROCESSING GLOBAL – WWW.MEATNEWS.COM MAY/JUNE 2006, p 26 )
From ancient regional traditions to new food product trends worldwide, algae are becoming the culinary trendsetters.
On the dining tables in Japan and France, aquatic algae are consumed in tonnes. Whether stewed or fried, whether in the form of soup or noodles, or as a flavoring mix on the side, in recent years, algae have clearly advanced to the status of culinary trendsetters. Viewed from a worldwide perspective, the use of algae as a leguminous food makes for the biggest share of this market in terms of both value and volume. This segment does, in fact, account for about two thirds of the total production, with Asiatic countries, where direct algoid food consumption is high, ranking on top.
This is a statistical fact which comes as little surprise, because people in that region have not only known algae for many thousands of years, but they have also come to really appreciate them thanks to the many nutritious and sensory qualities they bring to food preparation. Consumption of algae as a direct food has been a relatively unimportant factor in the western industrialised countries for a long period of time, but recent years have seen a distinct rise in consumer preference in this respect as well. In a more general context, however, it should be noted that, in this part of the world, algae have found frequent use as a food ingredient ever since the sixties, even though most often as a direct result of their techno-functional capabilities.
Immense diversity in type and kind
Algae are among the oldest organisms existing on our planet and can justifiably be classified as the bio-ancestral forerunners of life on earth. Among many other places of discovery, petrified remnants have been found in Wales, their age estimated at some 540 million years. Algae generally can be found in both salt and fresh water, with huge intra-groupal differences known to exist.
Take the monocellular microalgae for example, which are microscopically small, while their seaweed/macroalgae counterparts can be up to 50 metres in length. To the human eye, individual types mainly differ in terms of their colourants which, in turn, explains their botanical classification into blue, green, brown and red algae. Their diversity is nothing but gorgeous with some 30,000 to 40,000 different species and/or subspecies estimated to exist. Algae are so-called photosynthetic organisms, which produce their organic molecules from minerals, water, and carbon dioxide. This means that they also produce large amounts of oxygen as a result. As the first link in oxygen production on earth, cyanobacteria (blue or blue-green algae), therefore, also constitute the first link to animal life.
Human health sourced from the sea
Given their existence as aquatic organisms, algae draw a huge mineral wealth from the sea which, in turn, holds a great diversity, including mineral substances such as sodium, calcium, magnesium, potassium or phosphorus, together with such trace elements as iodine, iron, zinc, copper, selenium, fluorine or manganese. In short, no other products of nature are as rich in minerals, trace elements, amino acids and vitamins as algae. Red, brown and green algae come with an average of 30 to 36 per cent mineral content in their dry matter, in which far more than 80 different elements can be scientifically identified. In food processing and manufacturing, algae's protein content is of particular technological importance, too. In this context it must not be forgotten, however, that different species bring highly different protein quantities to the processing job: while the protein concentration of brown algae is only in a range from 5 to 11 per cent, some of their red counterparts offer a content of between 30 to 40 per cent, with the quality of protein delivered comparable to that of such highly proteinaceous plants as soybeans. Spirulina (a freshwater microalga) for example, with its high protein content of about 70 per cent in the dry matter, is, among other applications, particularly popular as a valuable supplemental additive in human food manufacturing.
First reports of algae being used as a human food originate from China, dating back to the year 2500 Be. But it was only in the 17th century that these marine plant species were cultivated in Japan to a larger extent. Returning to earlier times, these marine plants were also known in ancient Greece, even though their use was mostly as a medicinal remedy against helminthiasis (Le. infestation with parasitic worms). More into the medieval era, algoid foods were used to feed the poorest for a long time in several European regions. And in dire times of need, people living in coastal regions again and again cultivated algae as a livestock feed, placing rocks in inter-tidal areas to chiefly grow the fucus species. In addition, and dating back to the 16th century, people would routinely collect algae during the ebb tide interval, drying them to be used as fertilizer on the fields, a process, which in essence, is still proving its practical worth in this day and age.
Back to the human food chain, some 3 to 3.6 million tonnes of algae are currently harvested annually worldwide, with species coming from Europe and America being further processed into the most varied algae-based products. Demand for these types of substances has, in fact, shown a 25 per cent year-on-year increase, currently reaching a level of far more than 350,000 tonnes per annum. Over and above the more classical preparation into a leguminous foodstuff or a seasoning ingredient, algae have also established themselves as a base material for different additives being used in today's food industry.
In bio-technological detail, the polysaccharide algin or alginic acid (E-400), formed in the cellular walls, is the structure-building element of brown algae. The intracellular gel matrix gives the alga both its flexibility and its firmness. Algin is typically obtained as a by-product, when the wet process is employed to recover iodine from marine algae. But for use in and by the food industry, it is also directly extracted from brown algae, with its salts generally referred to as alginates which, in turn, are primarily used as thickening and! or gelling agents. Apart from sodium alginate (E-401), potassium alginate (E-402), ammonium alginate (E-403), calcium alginate (E-404) and propylene-glycol alginate (E-405) are the alginic acid salts most often used in food manufacture.
The viscosity of alginate solutions is primarily a dependent function of the molecular weight and the respective gegenion (a compensating ion), while its increase is first and foremost brought about by the presence and concentration of polyvalent cations (e.g. calcium) and the concentration in which they occur. It follows that viscosity can be readily adjusted to the specific level desired in any given case; and with calcium ions added in an accurately targeted manner, or by slightly acidifying sodium alginate solutions, gels, fibers and filmy sheets can be produced. In and by themselves, alginates are highly effective inspissating (thickening), stabilising and gelling agents. Used in concentrations between 0.25 and 0.5 per cent, they work to improve the stability of salad sauces, gravies, soups, bakery product fillings, and various types of convenience foods as well. Agar-agar is yet another polysaccharide or, more precisely, a galactose polymer capable of forming gelatin.
Produced from the cellular walls of some red algae or seaweed species, its use extends to numerous fields, with that of agar-based bacterial substrates one of the most widely known applications. As for use in the food industry, agar-agar's almost total indigestibility, its stabilising effects plus an ability to form heat-resistant gels are seen as the most significant properties.
More specifically, it is frequently employed in making sherbets and ice creams, most often in a 0.1 per cent dosage in combination with carob bean gum or gelatin. Dosages in the 0.1 to 1.0 per cent range are typical when agar is used with yogurt, cheese, sweets and bakery products; and finally, agar-agar is also employed to assist with preventing bread products from becoming stale too quickly.
Carrageenan, a complex mixture of different polysaccharides, is also obtained from red algae by extraction with hot water under slightly alkaline conditions, with drying or precipitation the subsequent step. When fractional precipitation of potassium ions is employed as an additional processing step, carrageenan can then be separated into various fractions which, comprising different monosaccharide building blocks, also differ in their solubility. Among those commercially used are the lambda-, kappa- and iotatype carrageenans, with the inherent properties most conducive to a given application determined by the specific type. As such, and in the presence of potassium and calcium ions, the kappa- and iota-types unfold their gelling activities, with kappa-carrageenans leading up to stiff and thermoreversible gels tending to produce synerisis, i.e. the separation of liquid from gel as a result of contraction. By adding water-soluble hydrocolloids, the structure of such gels can be materially improved.
By contrast, synerisis is not encountered in the presence of iota-type carrageenans which are relatively weak in their gelling ability at that, while those of the lambda-type are not capable of forming gels at all. As for the use of carrageenan in today's food processing practice, cooked ham manufacturing is clearly the single most important field of application.
In which connection, those of the kappa-type are particularly appropriate because of their solid gel structure which, after cooling, makes for good, firm-cutting sliceability and strong binding in the finished product. Looking somewhat further down the line, aquaculture is certainly in for a very promising future. For one thing, microalgae's productivity is beyond comparison: with their growth rate 10 times that of geophytes (soil-borne plants), their use potential in such diverse segments as human health and the environment is nothing but enormous.
For another, a great number of companies in various fields of industry have already discovered microalgae for their own business terrain: those tiny little fingerlings can be used to clean our air and water, to supplement human food, or to serve as a highly valuable cosmetic personal care product. Added to this is the fact that algae can even be employed as a future source of energy: reports have it that photosynthetic microalgae may, for example, be instrumental in converting biohydrogen to a form of energy that can be used in everyday practice.
But some of those innovative developments are likely not to materialize soon, because efficient mass production of algoid substances is currently still lacking. While this is so, the food industry could already be in for a virtual algae boom even before regular mass production gets underway. The reason for this is that these monocellular organisms contain tryptophane, a substance used by the human body to produce serotonin - the hormone of happiness, that is - and so a real reason to get algae mass production up to speed. MPG
May/June - www.meatness.com
( MEAT PROCESSING GLOBAL – WWW.MEATNEWS.COM MAY/JUNE 2006, p 26 )
From ancient regional traditions to new food product trends worldwide, algae are becoming the culinary trendsetters.
On the dining tables in Japan and France, aquatic algae are consumed in tonnes. Whether stewed or fried, whether in the form of soup or noodles, or as a flavoring mix on the side, in recent years, algae have clearly advanced to the status of culinary trendsetters. Viewed from a worldwide perspective, the use of algae as a leguminous food makes for the biggest share of this market in terms of both value and volume. This segment does, in fact, account for about two thirds of the total production, with Asiatic countries, where direct algoid food consumption is high, ranking on top.
This is a statistical fact which comes as little surprise, because people in that region have not only known algae for many thousands of years, but they have also come to really appreciate them thanks to the many nutritious and sensory qualities they bring to food preparation. Consumption of algae as a direct food has been a relatively unimportant factor in the western industrialised countries for a long period of time, but recent years have seen a distinct rise in consumer preference in this respect as well. In a more general context, however, it should be noted that, in this part of the world, algae have found frequent use as a food ingredient ever since the sixties, even though most often as a direct result of their techno-functional capabilities.
Immense diversity in type and kind
Algae are among the oldest organisms existing on our planet and can justifiably be classified as the bio-ancestral forerunners of life on earth. Among many other places of discovery, petrified remnants have been found in Wales, their age estimated at some 540 million years. Algae generally can be found in both salt and fresh water, with huge intra-groupal differences known to exist.
Take the monocellular microalgae for example, which are microscopically small, while their seaweed/macroalgae counterparts can be up to 50 metres in length. To the human eye, individual types mainly differ in terms of their colourants which, in turn, explains their botanical classification into blue, green, brown and red algae. Their diversity is nothing but gorgeous with some 30,000 to 40,000 different species and/or subspecies estimated to exist. Algae are so-called photosynthetic organisms, which produce their organic molecules from minerals, water, and carbon dioxide. This means that they also produce large amounts of oxygen as a result. As the first link in oxygen production on earth, cyanobacteria (blue or blue-green algae), therefore, also constitute the first link to animal life.
Human health sourced from the sea
Given their existence as aquatic organisms, algae draw a huge mineral wealth from the sea which, in turn, holds a great diversity, including mineral substances such as sodium, calcium, magnesium, potassium or phosphorus, together with such trace elements as iodine, iron, zinc, copper, selenium, fluorine or manganese. In short, no other products of nature are as rich in minerals, trace elements, amino acids and vitamins as algae. Red, brown and green algae come with an average of 30 to 36 per cent mineral content in their dry matter, in which far more than 80 different elements can be scientifically identified. In food processing and manufacturing, algae's protein content is of particular technological importance, too. In this context it must not be forgotten, however, that different species bring highly different protein quantities to the processing job: while the protein concentration of brown algae is only in a range from 5 to 11 per cent, some of their red counterparts offer a content of between 30 to 40 per cent, with the quality of protein delivered comparable to that of such highly proteinaceous plants as soybeans. Spirulina (a freshwater microalga) for example, with its high protein content of about 70 per cent in the dry matter, is, among other applications, particularly popular as a valuable supplemental additive in human food manufacturing.
First reports of algae being used as a human food originate from China, dating back to the year 2500 Be. But it was only in the 17th century that these marine plant species were cultivated in Japan to a larger extent. Returning to earlier times, these marine plants were also known in ancient Greece, even though their use was mostly as a medicinal remedy against helminthiasis (Le. infestation with parasitic worms). More into the medieval era, algoid foods were used to feed the poorest for a long time in several European regions. And in dire times of need, people living in coastal regions again and again cultivated algae as a livestock feed, placing rocks in inter-tidal areas to chiefly grow the fucus species. In addition, and dating back to the 16th century, people would routinely collect algae during the ebb tide interval, drying them to be used as fertilizer on the fields, a process, which in essence, is still proving its practical worth in this day and age.
Back to the human food chain, some 3 to 3.6 million tonnes of algae are currently harvested annually worldwide, with species coming from Europe and America being further processed into the most varied algae-based products. Demand for these types of substances has, in fact, shown a 25 per cent year-on-year increase, currently reaching a level of far more than 350,000 tonnes per annum. Over and above the more classical preparation into a leguminous foodstuff or a seasoning ingredient, algae have also established themselves as a base material for different additives being used in today's food industry.
In bio-technological detail, the polysaccharide algin or alginic acid (E-400), formed in the cellular walls, is the structure-building element of brown algae. The intracellular gel matrix gives the alga both its flexibility and its firmness. Algin is typically obtained as a by-product, when the wet process is employed to recover iodine from marine algae. But for use in and by the food industry, it is also directly extracted from brown algae, with its salts generally referred to as alginates which, in turn, are primarily used as thickening and! or gelling agents. Apart from sodium alginate (E-401), potassium alginate (E-402), ammonium alginate (E-403), calcium alginate (E-404) and propylene-glycol alginate (E-405) are the alginic acid salts most often used in food manufacture.
The viscosity of alginate solutions is primarily a dependent function of the molecular weight and the respective gegenion (a compensating ion), while its increase is first and foremost brought about by the presence and concentration of polyvalent cations (e.g. calcium) and the concentration in which they occur. It follows that viscosity can be readily adjusted to the specific level desired in any given case; and with calcium ions added in an accurately targeted manner, or by slightly acidifying sodium alginate solutions, gels, fibers and filmy sheets can be produced. In and by themselves, alginates are highly effective inspissating (thickening), stabilising and gelling agents. Used in concentrations between 0.25 and 0.5 per cent, they work to improve the stability of salad sauces, gravies, soups, bakery product fillings, and various types of convenience foods as well. Agar-agar is yet another polysaccharide or, more precisely, a galactose polymer capable of forming gelatin.
Produced from the cellular walls of some red algae or seaweed species, its use extends to numerous fields, with that of agar-based bacterial substrates one of the most widely known applications. As for use in the food industry, agar-agar's almost total indigestibility, its stabilising effects plus an ability to form heat-resistant gels are seen as the most significant properties.
More specifically, it is frequently employed in making sherbets and ice creams, most often in a 0.1 per cent dosage in combination with carob bean gum or gelatin. Dosages in the 0.1 to 1.0 per cent range are typical when agar is used with yogurt, cheese, sweets and bakery products; and finally, agar-agar is also employed to assist with preventing bread products from becoming stale too quickly.
Carrageenan, a complex mixture of different polysaccharides, is also obtained from red algae by extraction with hot water under slightly alkaline conditions, with drying or precipitation the subsequent step. When fractional precipitation of potassium ions is employed as an additional processing step, carrageenan can then be separated into various fractions which, comprising different monosaccharide building blocks, also differ in their solubility. Among those commercially used are the lambda-, kappa- and iotatype carrageenans, with the inherent properties most conducive to a given application determined by the specific type. As such, and in the presence of potassium and calcium ions, the kappa- and iota-types unfold their gelling activities, with kappa-carrageenans leading up to stiff and thermoreversible gels tending to produce synerisis, i.e. the separation of liquid from gel as a result of contraction. By adding water-soluble hydrocolloids, the structure of such gels can be materially improved.
By contrast, synerisis is not encountered in the presence of iota-type carrageenans which are relatively weak in their gelling ability at that, while those of the lambda-type are not capable of forming gels at all. As for the use of carrageenan in today's food processing practice, cooked ham manufacturing is clearly the single most important field of application.
In which connection, those of the kappa-type are particularly appropriate because of their solid gel structure which, after cooling, makes for good, firm-cutting sliceability and strong binding in the finished product. Looking somewhat further down the line, aquaculture is certainly in for a very promising future. For one thing, microalgae's productivity is beyond comparison: with their growth rate 10 times that of geophytes (soil-borne plants), their use potential in such diverse segments as human health and the environment is nothing but enormous.
For another, a great number of companies in various fields of industry have already discovered microalgae for their own business terrain: those tiny little fingerlings can be used to clean our air and water, to supplement human food, or to serve as a highly valuable cosmetic personal care product. Added to this is the fact that algae can even be employed as a future source of energy: reports have it that photosynthetic microalgae may, for example, be instrumental in converting biohydrogen to a form of energy that can be used in everyday practice.
But some of those innovative developments are likely not to materialize soon, because efficient mass production of algoid substances is currently still lacking. While this is so, the food industry could already be in for a virtual algae boom even before regular mass production gets underway. The reason for this is that these monocellular organisms contain tryptophane, a substance used by the human body to produce serotonin - the hormone of happiness, that is - and so a real reason to get algae mass production up to speed. MPG
May/June - www.meatness.com
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