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Volume 3 Special Issue 1 2009
POTATO III
How to reference: Canet W, Fernández C, Alvarez MD (2009) Some Objective Instrumental Methods for Evaluating the Texture of Solid Potato Tissue (Solanum tuberosum L.). In: Yee N, Bussell WT (Eds) Potato III. Food 3 (Special Issue 1), 1-12
Guest Editors
Nigel Yee, William T. Bussell
Unitec, New Zealand
www.unitec.ac.nz
Issue Information [PDF]
CONTENTS AND ABSTRACTS
Wenceslao Canet, Cristina Fernández, María Dolores Alvarez (Spain) Some Objective Instrumental Methods for Evaluating the Texture of Solid Potato Tissue (Solanum tuberosum L.) (pp 1-12)
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ABSTRACT
Techniques Paper: The paper presents different objective instrumental methods for studying the rheological behaviour of either fresh or thermally treated potato tissue at large and small deformations. It describes the methodology followed and the equipment used to perform fundamental objective assays of compression, tension, shear, stress-relaxation and creep compliance, and imitative direct texture profile analysis (TPA). It also shows the manner in which the force-deformation, deformation-time and force-time curves are used to obtain different rheological and textural properties. Some examples are given of the type of information that can be derived from them. Some refined measurements and procedures that complement recognized methods are proposed to improve the texture measurement of potato tissue. Since the results of objective methods depend on the experimental setup, some of the factors to be considered in each one have been included. Tests are performed on fresh and thermally-treated potato specimens, and indications are given of the best objective methods and rheological properties to represent the firmness of either fresh potato tissue or potato tissue that has been subjected to the different thermal treatments involved in the frozen potato production process.
Sylwester Furmaniak, Artur P. Terzyk, Leszek Czepirski, Ewa Komorowska-Czepirska, Joanna Szymońska, Piotr A. Gauden (Poland) Modeling of Sorption of Water on Potato and on Potato Starch (pp 13-17)
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ABSTRACT
Original Research Paper: It is well known that sorption isotherms of water vapour on foodstuffs are very important for design, modelling and optimization of important processes for example drying, aeration, predicting of stability and quality during packaging and storage of food. In this study we present water sorption data on potato and on potato starch measured for a few temperatures. Our results are described using the most applicable and advanced models of water sorption applied in the field of food engineering. The procedure of simultaneous description of multitemperature data provides the insights into the mechanism and energetics of water sorption on studied products.
Pietro Rocculi, Santina Romani (Italy), Federico Gómez Galindo (Portugal/Sweden), Marco Dalla Rosa (Italy) Effect of Minimal Processing on Physiology and Quality of Fresh-Cut Potatoes: a Review (pp 18-30)
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ABSTRACT
Invited Review: Fresh-cut fruit and vegetable are minimally processed products that have to maintain their quality (appearance, texture, flavour and nutritive value) similar to those of the fresh product. The fundamental principle underlying the quality of these commodities is that they are metabolic active tissues and, as a consequence, show physiological response to preparation procedures as well as to the environment created in the package in which they are enclosed. Minimal processing for fresh-cut potato production includes raw material selection, washing, peeling and cutting, pre-treatments, drying, weighing and packaging. The purpose of this review is to analyse the effects of the different minimal processing steps on the physiology and related quality of fresh-cut potatoes. Particular attention is given to the newest studies on processing innovation and innovative scientific approaches for a better understanding of fresh-cut products as biological systems. In this direction the use of ozone sanitization, natural dipping pre-treatments and/or coatings (e.g. edible film enriched in ascorbic and citric acid), and modified atmosphere packaging at high O2 levels result the most promising and non-invasive techniques for the preservation of fresh-cut potatoes. As far as physiological studies of the product are concerned, fundamental metabolic research for process optimisation and quality assurance is needed. For this aim isothermal calorimetry may provide a versatile tool to conduct fundamental metabolic studies of the effect of different processing steps on the quality and shelf-life of fresh-cut potatoes.
Elizabeth A. Donner, Qiang Liu, Walter J. Arsenault, Jerry A. Ivany, Peter J. Wood (Canada) Physicochemical and Nutritional Properties of Starch and Dry Matter from Organically and Conventionally Grown Potatoes (pp 31-38)
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ABSTRACT
Original Research Paper: The chemical composition, gelatinization, retrogradation, pasting, and in vitro starch digestibility of starch and dry matter obtained from Goldrush, Norland and Yukon Gold potatoes grown under organic and conventional conditions were investigated. The crystalline structure of potato starch was also examined using wide-angle X-ray diffraction. Total protein content of potato dry matter was significantly higher in organically grown potatoes. The free glucose levels were significantly higher in dry matter obtained from conventionally grown tubers. Phosphorus content of starch isolated from organic potatoes was significantly lower than that found in starch from conventionally grown potatoes. From rapid visco analysis (RVA), peak viscosity was significantly higher for all starches and dry matter from conventionally produced potatoes. Significant differences were found in peak time of starch and final viscosity of dry matter with respect to production method. Differential scanning calorimetry (DSC) showed some significant differences between production methods in onset temperature, peak temperature, conclusion temperature and enthalpy of gelatinization of starch. Retrograded potato starch and dry matter from conventionally produced potatoes had significantly larger enthalpy values than organic. Comparing digestibility in vitro, slowly digestible starch content of raw organic potato starch was significantly greater than that of raw conventional starch, while resistant starch content of raw organic starch was significantly lower than that of raw conventional starch. Rapidly digestible starch content of cooked conventional dry matter was significantly higher than that of cooked organic dry matter, yet resistant starch content was significantly lower than that found in the cooked organic dry matter.
Malin E. Sjoo, Ann-Charlotte Eliasson (Sweden), Karin Autio (Finland) Comparison of Different Microscopic Methods for the Study of Starch and Other Components within Potato Cells (pp 39-44)
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Original Research Paper: The microstructure of potato was studied by different microscopic techniques. The methods used were bright field (BFM), fluorescence (FM), confocal laser scanning (CLSM), scanning electron (SEM), and transmission electron (TEM) microscopy. The focus was on starch and structure of cells before and after cooking. Also components such as cell walls, protein, and pectin were identified by using different staining procedures. The use of different methods improved the interpretation of results and facilitated the identification of possible artifacts. The distribution of starch and proteins differed between tuber parts but also between adjacent cells. The amount of starch in individual cells clearly affected the shape of cells in cooked potatoes. Starch and cell shape were clearly visualised by all methods but TEM, which due to the high magnifications was better suited for studying cell walls and heat promoted separation of cells. CLSM was the preferred method for studying starch with minimal impact on the cell structure since artificial effects could be induced during preparation.
Piotr Tomasik (Poland) Specific Physical and Chemical Properties of Potato Starch (pp 45-56)
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ABSTRACT
Invited Review: Potato starch offers several unique properties essential for nutrition, and numerous non-nutritional applications. First of all, it is the sole native starch of anionic character. For that reason, potato starch combines, for instance, with proteins forming various complexes considered as potential biodegradable plastics. Potato starch is, practically, the sole starch variety containing a considerable amount of organically bound phosphorous. Hence, potatoes are an important source of phosphorous in a diet poor in fish. Potato starch distinguishes itself from other starches in the size of its granules which reach up to 150 µm in their diameter. Regular potato starch contains up to 27% amylose but, recently, also almost purely amylopectin (so-called waxy) starch and starches of enhanced content of amylose, so-called hylon starches, have become available through genetic modifications. Regular starches also contain up to 1.5% protein. While looking for a good source of protein suitable for the synthesis of spidroin (protein of the spider net) attention has been paid to genetic modifications of potatoes to replace genetically modified goat milk as a superior source of that protein. Potato starch granules swell much more readily than granules of other starches and resulting gels are much more viscous than gels of the same concentration from other starches. Specific properties of potato starch are manifested in results of several physical modifications such as gelatinization, thermolysis and pyrolysis, deep freezing, high pressure, ultrasounds, electromagnetic radiation (ionizing x-ray, neutron, α, β, and γ microwaves, ultraviolet, visible linearly polarized, infrared), low pressure glow plasma, corona discharges, the solvent effect. The unique properties of potato starch are also revealed in physicochemical modifications, that is, formation of the Werner type complexes with metal ions, all surface sorption, capillary, inclusion and channel complexes, and numerous chemical and enzymatic modifications.
Kazutaka Yamamoto, Kiyoshi Kawai, Ken Fukami, Shigenobu Koseki (Japan) Pressure Gelatinization of Potato Starch (pp 57-66)
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ABSTRACT
Invited Review: This article reviews the pressure gelatinization of starch with a special focus on potato starch which is a key food ingredient and an industrial raw material. First of all, the application of high hydrostatic pressure (HHP), as a novel processing parameter, to food processing is briefly overviewed with some historical backgrounds. It has been revealed in the last century that a starch-water mixture can be gelatinized only with HHP: without heating. In the HHP treatment of a starch system, attention should be paid to the ways of compression and difference in the properties between HHP- and heat-gelatinized starches. Physico-chemical changes of various starches after HHP treatment have been studied intensively. However, the behavior of pressure gelatinization has not been studied systematically, since most of the experiments have been carried out at fixed water (or starch) content with only a few treatment pressures. In addition, since potato starch is one of the most pressure-resistant starches, which impose experimental limitations for achievable maximum pressure, pressure gelatinization of potato starch has not been studied sufficiently. Recently, we have treated potato starch-water mixtures of various water (or starch) contents with treatment pressures from 400 to 1,200 MPa, and presented a state diagram of the HHP-treated samples. We expect that the behavior of pressure gelatinization and HHP-induced retrogradation will be understood in more detail with this approach utilizing the state diagram.
Tomasz Zięba (Poland) Resistant Starch in Food Products (pp 67-71)
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ABSTRACT
Invited Mini-Review: Resistant starch (RS) is the sum of starch and products of its degradation that are not digested in the small intestine of healthy individuals. Resistant starch has been categorized into the following types: 1) physically inaccessible or digestible resistant starch (e.g. starch present in partially ground cereals), 2) starch that occurs in its natural granular form (potato starch granules resistant to pasting, 3) retrograded starch (present in cooked-and-chilled potatoes) and 4) starches chemically or physically modified to be resistant to amylases. RS reduces the energy value and glycemic index of food products. Starches accessible to microorganisms present in the large intestine are of particular importance. The fatty acids formed due to fermentation processes favourably affect the metabolic processes by reducing cholesterol and triglycerides in human body. The formation of butyric acid in the final portion of the alimentary tract is particularly important in prevention of colon and colorectal cancer. RS content can be increased by adding it to the food products or by special preparation of the food products.
Marek Sikora, Magdalena Krystyjan (Poland) Interactions of Potato (Solanum tuberosum L.) Starch with Selected Polysaccharide Hydrocolloids – A Mini Review (pp 72-78)
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Invited Mini-Review: The state of knowledge on interactions of starches of different origins, and particularly of potato starch with polysaccharide hydrocolloids is presented. We explain that differentiated interactions between starch and the other polysaccharide hydrocolloids exist, and possible mechanisms are specified. The main phenomena occurring in aqueous systems of polysaccharide hydrocolloids result from incompatibility between starch and non-starchy hydrocolloids. These are phenomena occurring on phase boundaries, i.e. the leaching of amylose from starch granules, surrounding of swelled granules by long-chain polysaccharide hydrocolloids, and the inhibition of further swelling of starch granules.
Anna Pęksa, Elżbieta Rytel, Agnieszka Kita, Grażyna Lisińska, Agnieszka Tajner-Czopek (Poland) The Properties of Potato Protein (pp 79-87)
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ABSTRACT
Invited Mini-Review: About 75% of proteins present in potato (Solanum tuberosum) tubers are soluble in water or salt solutions (including 50% of protein fractions of molecular weight within 44 000-45 000 Da). The pH of these proteins, mainly tuberin or patatin, is usually low. They are reserve proteins, typical of potatoes, mainly glycoproteids, which can be easy precipitated in acids at pH 3-4. Low pH (≈ 5), depending on temperature, may cause irreversible destruction of tertiary structures and precipitation of tuberin proteins. On the other hand, when the pH is slightly acidic, solubility of the majority of potato proteins is dependent on ionic strength and temperature. Data in the literature show that surface properties of potato protein fractions may vary and that these differences can be significant. The results of these studies show that most fractions exhibit emulsifying properties, while tuberin is primarily responsible for foaming. Potato proteins, except prolamines, are of great biological and nutritional value. Extensive studies have been carried out on production methods for protein preparations from potato juice. The aim of these studies was to obtain potato proteins that exhibit functional properties that could be suitable for use in food product manufacturing.
Sissel Løkra, Knut Olav Strætkvern (Norway) Industrial Proteins from Potato Juice. A Review (pp 88-95)
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ABSTRACT
Invited Mini-Review: Industrial proteins constitute proteins of nutritious and functional values obtained from animal and plant sources, and recovered commercially on a large scale. Among the plant crop proteins, potato has up to recently been regarded only as a nutritious supplement to feeds, unsuitable in human foods due to low technical quality. Major potato proteins characterized by molecular size, are the 40-42 kDa patatin group (35-40%) and the protease inhibitor group of 7-21 kDa (25-50%). Although well-balanced in amino acid composition, and possessing valuable protein functionality, food utilization has been limited due to high levels of total glycoalkaloids (TGA) and phenolic compounds. Potato juice (PJ) from starch manufacturing is the major source of protein extraction. The voluminous and dilute protein solution (1-2%) has a complex composition and is high in organic matter; hence, the rigorous demands on the effluent require efficient recovery of protein and peptide fractions. The recovery methods from PJ that are reviewed here include precipitation with various acids, membrane separation and chromatographic adsorption. Precipitation with various acids, often in combination with heat coagulation, gives high recoveries but destroys functionality. Membrane separation (reverse osmosis, ultrafiltration) is better, but ultrafiltration is often difficult to perform and uneconomical due to filter fouling. As a gentle processing alternative, expanded bed adsorption (EBA) has been demonstrated as a scalable chromatographic method with the ability to separate the major protein groups from phenolic compounds and TGA, resulting in highly functional protein preparations. EBA, as well as other improvements in established technologies are now gradually moving potato proteins into a better position as an industrial protein.
Silke Hillebrand, Heike Naumann, Nina Kitzinski, Nils Köhler, Peter Winterhalter (Germany) Isolation and Characterization of Anthocyanins from Blue-fleshed Potatoes (Solanum tuberosum L.) (pp 96-101)
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ABSTRACT
Original Research Paper: During the last decade anthocyanin-related research has been intensified due to the fact that a high intake of anthocyanin-rich food has been linked to health-protecting effects. Pigmented potato (Solanum tuberosum L.) varieties constitute an important source of anthocyanins. So far, little information concerning the metabolism, bioactivity, and bioavailability of acylated anthocyanins has been published because it is still difficult to obtain pure pigments on a preparative scale. In our studies, the pigment composition of the blue-fleshed potato cultivars ‘Hermanns Blaue’, ‘Vitelotte’, ‘Shetland Black’, and ‘Valfi’ were examined. The preparative isolation of anthocyanins was carried out by applying two different methods of countercurrent chromatography (CCC), the so-called High-Speed Countercurrent Chromatography (HSCCC) and Low Speed Rotary Countercurrent Chromatography (LSRCCC), respectively. By application of LSRCCC, HSCCC, as well as preparative HPLC it was possible to isolate and characterize the major pigments, i.e. 3-p-coumaroylrutinoside-5-glucosides of petunidin, malvidin, and peonidin, of the four cultivars. From the cultivar ‘Hermanns Blaue’ LSRCCC enabled the isolation of the major pigment petunidin-3-p-coumaroylrutinoside-5-glucoside on a preparative scale. Furthermore, it was possible to separate and characterize several non-acylated 3,5-diglucosides, i.e. 3-rutinoside-5-glucosides of petunidin and malvidin, acylated 3,5-diglucosides, i.e. 3-feruloylrutinoside-5-glucosides of petunidin and malvidin as well as the 3-caffeoylrutinoside-5-glucoside of petunidin, and the p-coumaric acid derivative petunidin-3-p-coumaroylrutinoside. Purity and identity of the so-obtained anthocyanins were controlled by HPLC-DAD, ESI-MSn, and NMR-measurements.
Alfonso Totosaus (Mexico) The Use of Potato Starch in Meat Products (pp 102-108)
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ABSTRACT
Invited Mini-Review: Potato starch is one of the most non-meat ingredients employed in the meat industry. Starches had the ability to gelatinize with a considerable water uptake, improving cooking yielding and texture of emulsified or restructures meat products with minor effects on color. Application of starches in meat systems seems to be not quite adequate to allow the full functionality of starch. Gelatinization temperatures for most of native starches are above meat products thermal processing temperature, besides salts or sodium chloride presence increases this temperature interfering with the complete starch granule swelling. Nonetheless, potato starch lower gelatinization temperature close to meat products processing make it the most suitable extender for this kind of cooked meat products. This work is a revision about why potato starch is employed in meat systems with an acceptable functionality.
Piroska Szabó-Révész (Hungary), Anikó Szepes (Germany) Potato Starch in Pharmaceutical Technology – A Review (pp 109-117)
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Invited Mini-Review: Unmodified/native potato starch (Amylum solani) is a white, odourless and inert multifunctional excipient which is widely used not only in conventional pharmaceutical operations, such as tableting, capsule filling or granulation, but also in novel formulation technologies as a filler (diluent), binder or disintegrant. In order to improve processability or extend the range of potato starch application, different types of modification have been introduced. The present review describes the functional properties of potato starch which promote its utilization in pharmaceutical technology, provides an overview of practised starch modifications and summarizes the uses and applications of native potato starch and its modifications in drug formulation.
Duroy A. Navarre, Aymeric Goyer, Roshani Shakya (USA) Developing the Nutritional Potential of Potato (pp 118-124)
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Invited Mini-Review: Potatoes are the most consumed vegetable in the developed world and consumption is increasing in the developing world. Consequently, the phytonutrient content of potato can have a large impact on public health. Moreover, because of the high consumption even modest increases in tuber phytonutrient content can be important. Although already a good source of phytonutrients, little effort has been directed towards maximizing the nutritional potential of potatoes. Similarly, the rich genetic diversity of potatoes has barely been utilized for nutritional enhancement. Recent technological advances combined with increasing knowledge about which phytochemicals have health-promoting properties should facilitate the development of phytonutrient-enhanced potatoes. This review will focus on phenolic, glycoalkaloid, vitamin C and vitamin B9 (folate) content in potato and examine recent efforts to further increase tuber concentrations of these compounds.
Rong Tsao (Canada) Phytochemical Profiles of Potato and their Roles in Human Health and Wellness (pp 125-135)
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Invited Review: This review provides updated information related to the chemistry, biochemistry and biological activities of the major phytochemicals including carotenoids, anthocyanins, flavonoids, phenolic acids in potato (Solanum tuberosum L.). The antioxidant activities of these phytochemicals, either in the form of extracts or purified states were discussed. The health beneficial effects of potato phytochemicals, particularly polyphenols and carotenoids and their roles in reducing risks associated with cancer, cardiovascular disease and diabetes were also discussed.
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