The International Code for Starch Nomenclature
Please cite as: ICSN 2011, The International Code for Starch Nomenclature, (insert URL), accessed (insert date you viewed the page).
Terms are noted with their original sources, and definitions may have been modified by the conference participants to be more useful in archaeobotanical contexts. Uncited terms were coined and/or decided upon by the participants in the Internet Conference for Starch Nomenclature. Participants are listed at the foot of this page.
Starch grain / granule – a semi-crystalline ergastic substance formed in amyloplasts via the layering of amylose and amylopectin carbohydrate molecules around a central point (Fahn 1990, Esau 1977).
Starch grains have diagnostic morphological criteria that are specific to genera, species, and even some varieties of plants (Reichert 1913, Carlquist 1961).
in external granule morphology are generally sufficient to provide unambiguous
characterization of the botanical source, via optical microscopy” (Perez et al.
Native starch – in a state unaltered from that within the plant (Perez et al. 2009)
Transitory starch – Small, temporary starch grains produced in chloroplasts, discoidal in shape, the morphology of which is not genetically controlled (Denniston 1907, Reichert 1913)
Storage starch – Starch grains designed for long-term storage of energy, produced in the amyloplasts of seeds, roots, tubers, corms, fruits and rhizomes, the morphology of which is genetically controlled (Reichert 1913)
Resistant starch – starch that is not digested in the small intestine of humans (Champ 2004, Biliaderis 2009) Useful term for explaining why some starches survive and others do not.
Simple starch grain – grains that form singly (Fahn 1990)
Half-compound grain – a grain that forms in a single amyloplast with two or more centers and two or more sets of lamellae that are then completely surrounded by a larger, single, common set of lamellae (Fahn 1990, Reichert 1913)
Compound starch grain – grains that form in aggregates, or grains that have more than one center of formation within a single amyloplast (Fahn 1990)
Component grain/granule – a disarticulated but intact granule from a compound starch grain
Amorphous starch – a paste of starch that has no clear granular form (Reichert 1913)
Aggregates / Clumps – groupings of starch granules (Fahn 1990, Lindeboom et al. 2004)
Isolated – occurring singly (Reichert 1913)
Terms for defining assemblages of starch grains
Bimodal, Trimodal – having one, two, or three distinct size classes of grains
within the same plant. E.g., starches of species in the Triticeae tend to be
bimodal (Lindeboom et al. 2004, Jane et al. 1994, Jane 2009)
Conspicuous forms – the distinctive starch morphotypes in an assemblage (Reichert 1913)
Diagnostic – describing a set of morphological features that is unique to a plant taxon and allows identification of that form. Can refer to both a single "type" grain and to an assemblage (Reichert 1913)
Characteristic – describing a set of morphological features that are typical of a taxonomic group or plant organ, but that do not necessarily allow for a secure identification (sensu Reichert 1913)
Isomorphic – all of the grains from the species have the same general shape
Heteromorphic – the starches from the species have a variety of shapes
When at all possible, a three-dimensional term should be used to describe the basic morphology of a starch grain. When not possible, two-dimensional terms may be used to describe the shape in plan view and in profile, or they may be used to augment a three-dimensional description.
Circular – appearing as a circle in which all radii are of equal length
Oval – having a rounded and slightly elongated outline
Semicircular – part of a circle or oval
Triangular – having three well-defined sides
Square – having four equal sides
Rectangular – having four sides with opposite sides parallel and of equal length
Trapezoidal – having four sides, one pair of which are parallel
Polygon – having more than four sides; note number of sides in description
Elongated – lanceolate to conical (Reichert 1913)
Ends equal (also, Rod-shaped) or One end attenuated (Reichert 1913)
Spherical – a sphere in which all radii are equal length (defined in Reichert 1913, used in Lindeboom et al. 2004)
Hemispherical – half a sphere (Reichert 1913)
Ovoid – egg-shaped, one end smaller than the other (Reichert 1913)
Ellipsoid – ovoid with both ends equal in size (Jane 1994)
Pyriform – shaped like a pear (Reichert 1913)
Cylindrical – having a circular base and top, both of equivalent size (Reichert 1913)
Quadrangular – having six sides (Reichert 1913)
Conical – having a flat circular base and tapering to a pointed top (Reichert 1913)
Conoid – one half of the grain is conical (two straight subparallel sides), while the other is ovoid or hemispherical. Differs from conical in that the base is ovoid, not a flat circle.
Biconical – a 3d shape made by two cones that share the same base.
Symmetrical – Both cones of equal height
Asymmetrical – Cones of unequal height
Lenticular – bi-convex (Reichert 1913)
Plano-convex – flat on one side, convex on the other (Reichert 1913)
Concave-convex – curving inward on one side, curving outward on the other
Reniform – kidney-shaped (Reichert 1913)
Prismatic – any three dimensional shape that has two equivalent two-dimensional faces on opposite ends and a parallel axis between the faces, e.g., a cylinder (Reichert 1913)
Polyhedral – having many faces that are not necessarily of the same two-dimensional shape (Reichert 1913)
Wedge-shaped / Compressed – flattened, of equal thickness throughout, or thicker on one end (Reichert 1913)
Discoidal – flat and round in plan view (Reichert 1913)
Terms to use with basic three-dimensional descriptors
Oblate – Flattened at the poles. Can be used as a modifier with ellipsoid, ovoid, pyriform, conoid, biconoid or cylindrical.
Prolate – Lengthened in the polar diameter. Can be used as a modifier with ellipsoid, ovoid, pyriform, conoid, biconoid or cylindrical.
Scalene – All three main diameters unequal length. Can be used as a modifier with ellipsoid, pyriform, ovoid, conoid, biconoid or cylindrical.
Angular – having acute angles where sides meet (Reichert 1913)
Compressed/Flattened – having a smaller dimension in one plane than in another (Reichert 1913)
Curved – having a smooth bend in the form (Reichert 1913)
Recurved – curved backward or inward, bow-shaped
Planed – having a flat surface form (Reichert 1913)
Rounded off – having smooth corners (Reichert 1913)
Sharp-edged – having angular corners (Reichert 1913)
Areas of the Starch Grain and Features
Details of the starch grain including the hilum, cross, lamellae, fissures, and surface features should be described in detail. The area of the grain in which these features occur should be specified in the description.
Areas of the starch grain
– the edge of the grain in any view (Reichert 1913)
Proximal – in the end of the grain where an eccentric hilum occurs (Reichert 1913)
Mesial – referring to the central part of the grain (Reichert 1913)
Distal – in the end of the grain away from the eccentric hilum (Reichert 1913)
Narrow aspect – the view of a compressed grain when rotated out of plan view into a side view (Reichert 1913)
Hilum – The central point around which the layers of a starch grain form (Fahn 1990, Esau 1977) Descriptors of hila follow:
Centric/Eccentric – occurs within or outside of the geometric center of the grain (Reichert 1913, Fahn 1990)
Distinct/Indistinct – can be seen easily or has less clarity (Reichert 1913)
Spherical – round in three dimensions (Reichert 1913)
Lenticular – the short axis of the grain is parallel to the shortest diameter of the hilum, which is centrally located, and the lamellae are usually of uniform thickness (Reichert 1913)
Elongate – the axis of the greatest diameter of the grain is parallel to the greatest diameter of the hilum, which is central, and the lamellae are rather uniform (Reichert 1913)
Invisible – is not apparent (Reichert 1913)
Obscured – not visible due to some other feature of the grain, such as a fissure (Reichert 1913)
Solid – grains with no apparent hilum, central cavity, or cracks (Reichert 1913)
Central cavity – there exists an open area around the hilum that may have a distinct form (Reichert 1913)
Refractive – the hilum area changes from dark to light as the plane of focus is moved through the hilum and the light bends. (sensu Reichert 1913)
Cross – an optical interference pattern that occurs when objects that form with layers, such as starch grains, are viewed using cross-polarized light. Descriptors for the cross follow:
Centric/Eccentric – in or outside of the geometric center of the grain (Reichert 1913)
Distinct/Indistinct – can be seen easily or has less clarity (Reichert 1913)
Symmetric/Asymmetric – having similarity in corresponding components of the cross, or having lack of similarity
Lines Thick/Thin – width of cross arms (Reichert 1913)
Lines Straight/Curved – extending in one direction or bending (Reichert 1913)
Confused – distorted from a distinct X form, often by interference from fissures (Reichert 1913)
Ragged/Clean Cut – irregular and jagged or regular and well-defined (Reichert 1913)
Sharply defined – having a large difference between the coloration of the figure and that of the surrounding grain (Reichert 1913)
Quadrants – the areas between the dark lines of the figure (Reichert 1913)
Numbers of arms – can differ in some species, so should be noted if significant
Length of arms – short, long, etc.
Degree of Polarization – a somewhat subjective assessment of the prominence of the cross. Described as Low, Fair, High, Very High etc. (Reichert 1913)
Cracks / Fissures – fissure lines in a starch grain, frequently emanating from the hilum, and often due to pressure between grains as they form within the plant (Reichert 1913). Descriptors of cracks as related to hilum position follow:
Unfissured – having no fissuring. Can refer to a percentage of a population of starch grains, some of which are Fissured. (Reichert 1913)
Radial – spreading from the center outward (Reichert 1913)
Perpendicular – at a right angle to the plane of the hilum (Reichert 1913)
Parallel – in the same plane and equidistant along the line of the hilum (Reichert 1913) Stellate – star-shaped (Reichert 1913)
Transverse – extending at a right angle to the long axis of the grain (Reichert 1913)
Longitudinal – extending along the long axis of the grain (Reichert 1913)
Oblique – neither perpendicular nor parallel (Reichert 1913)
Delicate – thin and faint in appearance (Reichert 1913)
Ragged/Clean Cut – irregular and jagged or regular and well-defined (Reichert 1913)
Regular/Irregular – even or uneven in geometry (Reichert 1913)
Branching – having subdivisions of the main fissure, often Lateral (Reichert 1913)
Mesial longitudinal cleft – a large, deep and variably ragged interior crack that runs parallel to the long axis of the grain, a characteristic of many legume starches.
Lamellae – growth layers of a starch grain (Reichert 1913). Descriptors of lamellae follow:
Lamellated /Non-Lamellated – having or not having lamellae. Can refer to a starch grain or a portion thereof (Reichert 1913)
Concentric/Eccentric – lamellae of uniform or of non-uniform thickness (Reichert 1913)
Complete or Continuous/Incomplete – extend through the entire grain or through part of the grain only (Reichert 1913)
Distinct/Indistinct – clearly or not clearly defined (Reichert 1913)
Coarse /Fine – wide or narrow lines (Reichert 1913)
Uniform – of the same properties throughout (Reichert 1913)
Knobby – having rounded
projections (Reichert 1913)
Rough – coarse in texture (Reichert 1913)
Smooth – having a surface free from irregularities (Reichert 1913)
Cleft – having an elongate central cavity (Reichert 1913)
Granular – appearing to be covered with small particles (Reichert 1913)
Reticulate – having a pattern resembling a net (Reichert 1913)
Wrinkled – having many irregular shallow fissures (Reichert 1913)
Pressure facets – indentations that occur during formation of compound starch grains (Reichert 1913)
Projections – areas that extend beyond the main surface of the grain (Reichert 1913)
Depressions – indentations not necessarily due to formation in compound grains (Reichert 1913)
Elevations – raised areas, defined in contrast to depressions (Reichert 1913)
Bulge – an area that expands from the surface, used as a noun (Reichert 1913)
Indentations – depressions that are larger than Depressions (Reichert 1913)
Pores – refer to indentations that are either surface depressions or openings to Serpentine Channels that penetrate into the interior of the grain (Fannon et al. 1992, 1993, 2004).
Macropores have diameters larger than 50 nm
Mesopores have diameters between 2 and 50 nm
Micropores have diameters smaller than 2 nm (Sing et al. 1985).
For Surface Cracks and Fissures, see descriptors in previous section. Also:
Broad – wide (Reichert 1913)
Long – extending for more than half the length of the axis (Reichert 1913)
Deep – appearing to extend about halfway into the grain (Reichert 1913)
Mesial – parallel to the central and long axis of the grain (Reichert 1913)
Equatorial groove (Williams and Bowler 1982) – the linear figure viewable when lenticular grains are turned on edge
Modified starch terms: descriptions of damage to starches
Gelatinization – the loss of a clear,
geometrically-defined shape and structure due to heat exposure during cooking
or other processing including grinding or pounding (Reichert 1913)
The loss of a clear, geometrically-defined shape and structure due to heating, caused by the break down of the crystalline portions of the starch grains. Fully gelatinized starches retain no form and are a thick slurry. (Tester 1997)
"The disruption of the granular order [and] . . . [t]he collapse (disruption) of molecular orders (breaking of H-bonds) within the granule, along with all concomitant and irreversible changes in properties such as water uptake, granular swelling, crystallite melting, birefringence loss, starch solubilization and viscosity development." (Biliaderis 2009)
Retrogradation – if the heating source is removed and the gelatinized mass is allowed to stand undisturbed, inter-molecular bonds will form between amylose molecules and create a semi-structured gel. In other words, gelatinized starch grains may not remain separate, but can create a large mass. Some remnants of formerly intact granules can retain birefringent properties within the paste. (Jacobson et al. 1997)
Paste – seems to refer to a mixture of cooked foodstuffs that includes some percentage of starch. An example would be a bread dough or a cake batter. (Johnson et al. 1990)
Pasting – When gelatinized starches blend into each other and become a single mass (Biliaderis 2009)
Melting – The very high-temperature breakdown of the crystalline portion of the starch that occurs in conditions of low water content. (Biliaderis 2009)
Swelling – the expansion of the starch grain along one or more axes (Willams and Bowler, 1982)
The expansion of a starch grain due to the uptake of water (which occurs reversibly when not heated, but irreversibly as an aspect of gelatinization). (Biliaderis 2009)
Fragment – a part of an entire grain (Babot 2003)
Disjoining – the separation of a compound starch (Babot 2003)
Collapse – the complete loss of structured form (Williams and Bowler, 1982)
Flat relief – the lack of visibility and reduced contrast under brightfield light, due to loss of water. (Babot 2003)
Ghosts – granule envelopes with no remaining contents (Obanni and BeMiller 1995)
Truncated – The breaking off of portions of starches as a result of milling (Babot 2003)
Burst – starch grains in which the inner material has expanded beyond the original margin of the grain (Babot 2003)
Exudate – when the interior material of the starch breaks through the outer margin. (Messner and Schindler 2010)
Saddle – a doubly-convex shape that is characteristic of partially-gelatinized lenticular starches (e.g., those from Triticeae). (Hoseney et al. 1977)
Puckered – a lenticular starch which is partially gelatinized and very swollen in the xy plane, somewhat expanded tangentially along the xy plane, but not very swollen in the z direction, and with a margin that has more curves than a saddle shape. (Bowler et al. 1980)
Crack – a fissure in the grain resulting from processing. The area of the grain in which crack occurs should be specified, e.g., surface, interior, margin, etc.
Fractured – when the fissures dividing a grain are so complete that portions of the grain are removed.
Dented – the presence of depressions in the surface of grains (Babot 2006).
Pitting – deep excavated areas on the surface of a starch due to the action of enzymes (modified from French 1984, Juan-Tresserras 1990-92)
Shrinkage – reduction in size on one or more axes due to loss of water (Radley 1943)
Corroded – having one or more of
the lamellae removed from the surface of a starch grain by some sort of
digestive process (Reichert 1913)
Hilum projections – pronounced rounded, irregular or star-shaped cracks originating at the hilum, which appear as a dark center under brightfield and cross-polarized light (Babot 2003)
Hilum opening – the increased opening of hilum by the loss of water. (Babot 2003, 2006)
Presence/Loss – due to damage, referring to any feature of the starch grain as described above, and not occurring in the native state
Babot, P. 2003. Starch grain damage as an indicator of food processing, in, Hart, D.M. and Wallis, L.A., (Eds.), Phytolith and starch research in the Australian-Pacific-Asian regions: the state of the art, Terra Australis 19, Pandanus Books, Canberra, pp. 69-81.
Babot, P. 2006. Damage on starch from processing Andean food plants, in, Torrence, R. and Barton, H., (Eds.), Ancient starch research, Left Coast Press, Walnut Creek, California, pp. 66-67, 70, Plates 31-32.
Biliaderis, C.G. 2009. Structural transitions and related physical properties of starch, in, BeMiller, J. and Whistler, R., (Eds.), Starch: Chemistry and Technology, 3rd edition, Academic Press, Amsterdam, pp. 293-373.
Bowler, P., Williams, M.R., Angold, R.E. 1980. A hypothesis for the morpohological changes which occur on heating lenticular wheat starch in water. Starch/Stärke 32:186-189.
Carlquist, S. 1961. Comparative Plant Anatomy: A guide to taxonomic and evolutionary application of anatomical data in angiosperms. Holt, Reinhart, and Winston, New York.
Champ, M.M.-J. 2004. Physiological aspects of resistant starch and in vivo measurements. AOAC International 87:749-755.
Denniston, R.H. 1907. The growth and organization of the starch grain. Transactions of the Wisconsin Academy of Sciences, Arts, and Letters. Vol. XV pp. 664-708.
Esau, K. 1977 (1960). Anatomy of Seeds Plants. John Wiley and Sons,
Fahn, A. 1990 (1967). Plant Anatomy. Pergamon Press, Oxford.
Fannon, J.E., Hauber, R.J., BeMiller, J.N. 1992. Surface pores of starch granules. Cereal Chemistry 69:284-288.
Fannon, J.E., Shull, J.M., BeMiller, J.N. 1993. Interior channels of starch granules. Cereal Chemistry 70:611-613.
Fannon, J.E., Gray, J.A., Gunawan, N., Huber, K.C., BeMiller, J.N. 2004. Heterogeneity of starch granules and the effect of granule channelization on starch modification. Cellulose 11: 247-254.
French, D. 1984. Organization of starch granules, in, BeMiller, J. and Whistler, R., (Eds.), Starch: Chemistry and Technology, 3rd edition, Academic Press, Amsterdam, pp. 183-247.
Hoseney, R.C., Atwell, W.A., Lineback, D.R. 1977. Scanning electron microscopy of starch isolated from baked products. Cereal Foods World 22:56-60.
Jane, J., Leas, S., Zobel, H., Robyt, J.F. 1994. Anthology of Starch Granule Morphology by Scanning Electron Microscopy. Starch/Stärke 46:121-129.
Jane, J. 2009. Structural Features of Starch Granules II, in, BeMiller, J. and Whistler, R., (Eds.), Starch: Chemistry and Technology, 3rd edition, Academic Press, Amsterdam, pp. 193-237.
Jacobson, M.R., Obanni, M., BeMiller, J.N. 1997.
Retrogradation of Starches from Different Botanical Sources. Cereal
Johnson, J.M., Davis, E.A., Gordon, J. 1990. Interactions of Starch and Sugar Water
Measured by Electron Spin Resonance and Differential Scanning Calorimetry. Cereal Chemistry 67:286-291.
Juan-Tresserras, J. 1990-1992. Procesado y preparación de alimentos vegetales para consumo humano. Aportaciones del estudio de fitolitos, almidones y lípidos en yacimientos arqueológicos prehistóricos y protohistóricos del cuadrante NE de la Península Ibérica. Tesis Doctoral, Universitat de Barcelona, Barcelona. Inédito.
Lindeboom, N., Chang, P.R., Tyler, R.T. 2004. Analytical, Biochemical and Physicochemical Aspects of Starch Granule Size, with Emphasis on Small Granule Starches: A Review. Starch/Stärke 56: 89–99.
Messner, T., Schindler, B. 2010. Plant processing strategies and their affect upon starch grain survival when rendering Peltandra virginica (L.) Kunth, Araceae edible. Journal of Archaeological Science, 37:328-336.
Obanni, M., BeMiller, J.N. 1995. Ghost microstructures of starch from different botanical sources. Cereal Chemistry 73: 333-337.
Perez, S., Baldwin, P.M., Gallant, D.J. 2009. Structural Features of Starch Granules I, in, BeMiller, J. and Whistler, R., (Eds.), Starch: Chemistry and Technology, 3rd edition, Academic Press, Amsterdam, pp. 149-192.
Radley, J.A. 1943. Starch and its derivatives, Second Edition, Chapman y Hall Ltd., London.
Reichert, E.T. 1913. The Differentiation and Specificity of Starches in Relation to Genera, Species, etc., Carnegie Institute, Washington DC.
Sing, K.S.W., Everett, D.H., Haul, R.A.W., Moscou, L., Pierotti, R.A., Rouquerol, J., Siemieniewska, T. 1985. Reporting physisorption data for the gas/solid systems with special reference to the determination of surface area and porosity. Pure and Applied Chemistry 57, 603-619.
Tester, R.F. 1997. Properties of damaged starch granules: composition and swelling properties of maize, rice, pea ad potato starch fractions in water at various temperatures. Food Hydrocolloids 11:293-301.
Williams, M.R., Bowler, P. 1982. Starch gelatinization: A morphological study of Triticeae and other starches. Starch/Stärke 34:221-223.
Authors of The 2001 Internet Conference for Starch Nomenclature
Linda Scott Cummings