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Interciencia ISSN: 0378-1844 [email protected] Asociación Interciencia Venezuela

López Mata, Lauro Proteins, amino acids and fatty acids composition of nuts from the mexican endemic rarity, pinus maximartinezii, and its conservation implications Interciencia, vol. 26, núm. 12, diciembre, 2001, pp. 606-610 Asociación Interciencia Caracas, Venezuela

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How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative PROTEINS, AMINO ACIDS AND FATTY ACIDS COMPOSITION OF NUTS FROM THE MEXICAN ENDEMIC RARITY, Pinus maximartinezii, AND ITS CONSERVATION IMPLICATIONS

Lauro López-Mata

SUMMARY

Seeds of blue pine, Pinus maximartinezii, have long been contains 18 different amino acids, including all the essential used for human consumption. However, no chemical analysis of ones, and six different fatty acids; of these about 84% are unsat- its nutrient components has been carried out. In this paper, the urated. Nuts of blue pine are of outstanding dietary value and content of kernel proteins, amino acids and fatty acids is re- appear to be a promising resource, but the impact of seed har- ported and compared with some pinyon pines and other nut spe- vesting size on the population stability needs to be thoroughly cies. Proximate analysis showed that blue pine contains about evaluated in order to insure its sustainable use. A conservation 31% crude protein, 66% defatted protein, 42% crude fat, 2% strategy for P. maximartinezii, should urgently focus on protect- carbohydrates, 9% crude fibre, 4% ash, and 4% moisture. It ing the specific habitat where this endemic rarity occurs.

RESUMEN

Las semillas del pino azul, Pinus maximartinezii, han sido análisis proximal mostró que el pino azul contiene 31% de proteí- usadas desde hace mucho tiempo para consumo humano. Sin em- na cruda, 66% de proteína desgrasada, 42% de grasa cruda, 2% bargo, ningún análisis químico de sus componentes nutritivos ha de carbohidratos, 9% de fibra cruda, 4% de cenizas y 4% de hu- sido llevado a cabo. En este artículo se reporta el contenido de medad. Contiene 18 amino ácidos distintos, incluyendo a todos proteína, amino ácidos y ácidos grasos de su nuez y se le compa- los esenciales, y seis ácidos grasos diferentes, 84% de ellos insa- ra con algunas especies de pinos piñoneros y otras nueces. El turados. La nuez del pino azul es de valor dietético sobresaliente

Introduction are native to Mexico (Farjon nuts rank high in food value des sensu Little and Critch- and Styles, 1997; Little and among wild and commercial field (1969) bears one of the One of the greatest number Critchfield, 1969; Perry, 1991). nuts (Crawford, 1995; Botkin largest seeds among the edible of pine species throughout the Of these, nearly a dozen pro- and Shires, 1948; Duke, 1989; pine nuts world-wide (Rze- world is found in México duce edible seeds with highly Duke and Atchley, 1986; Han dowski, 1964). Nevertheless, (Farjon and Styles, 1997; nutritious nuts and palatable and Hwang, 1990; Lanner, although seeds of P. maximar- Martínez, 1948; Perry, 1991; flavor that makes them worth 1981; Sagrero-Nieves, 1992; tinezii have been used for a Styles, 1993). About 50% of gathering (Crawford, 1995; Yoon et al., 1989). long time as a source of food the approximately 100 pine Duke, 1989). It has been well Pinus maximartinezii (Rze- for the local population, their species currently recognized documented that pinyon pine dowski), subsection Cembroi- chemical analysis has been ne-

KEY WORDS / Pinus maximartinezii / Rare and Endemic Pine / Conservation / Dietary Value / Chemical Composition / Recibido: 12/06/2001. Aceptado: 22/10/2001

Lauro López-Mata. Biologist, Uni- graduados. Ph.D. in Biology, tituto de Recursos Naturales, llo, Texcoco, Estado de Méxi- versidad Nacional Autónoma de University of North Caroline, Colegio de Postgraduados, co, México. México (UNAM). M.Sc. in Chapel Hill, USA. Researcher UNAM. Address: Colegio de e-mail: [email protected] Botany, Colegio de Post- and Professor in Botany, Ins- Postgraduados, 56230 Monteci-

606 0378-1844/01/12/606-05 $ 3.00/0 DEC 2001, VOL. 26 Nº 12 y parece ser un recurso promisorio. Sin embargo, el impacto de la sostenido. Una estrategia de conservación para P. maximartinezii magnitud de la cosecha de semillas sobre la estabilidad poblacio- debe concentrarse en la protección del hábitat donde ésta rareza nal necesita ser cuidadosamente evaluada para asegurar su uso endémica ocurre.

RESUMO

As sementes do pinho azul, Pinus maximartinezii, têm sido de umidade. Contém 18 amido ácidos distintos, incluindo a usadas desde muito tempo para consumo humano. Porém, não todos os essenciais, e seis ácidos grassos diferentes, 84% deles foi feita nenhuma análise química de seus componentes insaturados. A castanha do pinho azul é de valor dietético nutritivos. Neste artigo se reporta o conteúdo de proteína, amido sobressalente e parece ser um recurso promissório. Porém, o ácidos e ácidos grassos de sua castanha e é comparado com impacto do tamanho da colheita de sementes sobre a algumas espécies de pinhos, pinheiros e outras castanhas. A estabilidade populacional necessita ser cuidadosamente avaliada análise proximal mostrou que o pinho azul contém 31% de para assegurar seu uso sustentado. Uma estratégia de proteína crua, 66% de proteína sem gordura, 42% de gordura conservação para P. maximartinezii deve concentrar-se na crua, 2% de carboidratos, 9% de fibra crua, 4% de cinzas e 4% proteção do habitat onde esta rareza endêmica ocorre.

glected so far. This paper re- ports the chemical composition of P. maximartinezii nuts including a proximate analysis, proteins, amino acids, and fatty acids contents, and in- tends to attract attention on the importance of ecological knowledge within the context of its conservation and sustainable management. P. maximartinezii, com- monly known as Martinez pine, Zacatecas pine or blue pine, is a rare, endemic and threatened species known only from a single, small and local- ized population in the south- ernmost state of Zacatecas, Mexico (Rzedowski, 1964). Blue pine is distributed on the Sierra de Morones, approximately at 21º20’-21º22’ N and 103º12’-103º15’ W and from 1650 to 2500m elevation on a Figure 1. Geographic distribution of the endemic rarity, Pinus maximartinezii Rzedowski at Juchipila mountain locally known as county, Zacatecas State, México. Cerro de Piñones, Juchipila county (Figure 1). The species pling to estimate densities on (brown when ripe) and of up wingless seeds that are excep- is restricted to sedimentary any stands. to 2kg fresh weight. Cone tionally large, ranging 17.5- calcareous substrates all over P. maximartinezii grows scales open widely when ripe, 27.4mm long, 9-13.1mm wide, its range, however, it is rela- sparsely on flat terrain and releasing seeds soon after 7-10.2mm thick and 4.8-7.3 tively common on rock out- more densely on low to deep maturation. They usually open mg fresh weight. crops and limestone soils on slopes. Trees are usually 5- in September-October, after Local weather is semiarid, strong slopes (30-55°) with 15m in height and 10-30cm in the rainy season and before with temperatures from 18 to rolling rocks. Donahue and diameter at breast height the first fall frost. After seed 22°C. Approximately 75% of Mar-López (1995) described (DBH). In humid protected ra- dispersion cones remains at- the annual rainfall, estimated superficial soils as sandy vines they may reach 20-22m tached to the shoots or limbs in about 700-850mm, occurs loams with a pH of 7.2-7.5 on and, exceptionally, 110cm for two years. On mast years, during June-September. The West slopes and as clay loams DBH. The crown is rather seeds may fall over a period frost-free period is approxi- with pH of 6.8-7.0 on South- open and rounded, with large of 6-8 weeks. They are mately 275 days, from mid west slopes. These authors es- somewhat horizontal and pen- shelled, stoned, and susceptible February to November. Frost timated the total number of dent branches. Cones are to predation by a local gray periods occur mostly in De- mature trees in 2000-2500 in- borne singly or in clusters of squirrel and blue jay birds, cember or January, but may dividuals. However, their ob- 2-3 on the tip of the shoots; both of which are also dis- occasionally be present by mid servations must be taken with they are oblong and extremely persal agents. P. maximarti- November. Three major causes caution because they did not large, 18-25cm by 10-15cm at nezii, as all pinyon pines in threat the persistence of P. conducted a systematic sam- the widest portion, green the Haploxylon group, has maximartinezii: (1) Local habi-

DEC 2001, VOL. 26 Nº 12 607 TABLE I lowest in carbohydrates, rela- PROXIMATE ANALYSIS OF Pinus maximartinezii NUTS AND tively high in fiber and ash, OTHER NINE EDIBLE NUTS OF SELECTED PINE SPECIES and average in moisture (Table I). Other edible nut pine spe- Species Protein Fat Carbohydrates Fibre Ash Moisture cies such as P. monophylla (%) (%) (%) (%) (%) (%) and P. quadrifolia are among the lowest in crude protein and P. cembra 17-18 50-59 17 1.0 — — the highest in carbohydrates. P. cembroides 19 60-65 13.8 1.8 3.2 2.7 On the other hand, P. cembra, P. edulis 14.3 61 18.1 1.1 2.7 3.0 P. cembroides, P. edulis, P. P. koraiensis 17-18 65-67 12 4.8 2.2 4.4 koraiensis, and P. sibirica con- P. maximartinezii 31.3/65.6* 42.5 2.4 8.8 4.3 5.0 tain intermediate quantities of P. monophylla 9.5 23 54 1.1 2.4 10.2 both crude protein and carbo- P. pinea 34 48 6.5 1.4 — — hydrates. P. maximartinezii P. quadrifolia 11 37 45 1.1 2.4 4.9 compares favorably with the P. sabiniana 28-30 54-57 8 — — — Italian stone pine P. pinea, the P. sibirica 17 60-64 12 — — — Korean pine P. koraiensis, the Siberian pine P. sibirica, and * Defatted protein content the digger pine P. sabiniana. Blue pine is similar to Italian tat fragmentation directly re- Proximate analysis Amino acid analysis stone pine in protein content, lated to recent land-use as well as in carbohydrates changes, resulting in a great Three replicates were ex- Amino acid composition and fats, but significantly surface area reduction of its amined for oil, protein, ash, was analyzed by ion exchange higher in fiber (Table I). P. natural range as well as in the and moisture contents. Ash chromatography following the maximartinezii contains more species habitat deterioration was determined by incinera- method of Lucas and Sotelo crude protein than both, P. and soil erosion; (2) Overgraz- tion in a muffle furnace at (1982). Defatted samples were koraiensis and P. sibirica and ing and induced forest fires, 525ºC (AOAC, 1984). Nitro- hydrolyzed with HCl (6.0 mol/l) is similar to that of P. s a b i - which directly prevent seed- gen content was estimated by at 145ºC for 4h. At the end of niana. It should be noticed lings recruitment; and (3) The the Kjeldahl method, and hydrolysis, the hydrolysate that for pines, defatted protein current seed over-harvesting crude protein content was was adjusted to pH 6.8. Ac- is not directly comparable to and illegal national and inter- calculated using the conver- cording to Lucas and Sotelo the usual nut analysis; there- national trade. By virtue of sion factor Nx6.25. Crude fi- (1982), 1ml hydrolysate was fore, it is not possible to com- these facts blue pine is an en- ber, fat, and moisture were diluted with a 1ml buffer pH pare defatted protein contents dangered species after the determined in accordance 1.3, and from this dilution a among pine species because Mexican norm, NOM-059- with the standard methods of 100µl aliquot was injected on data has not been reported. ECOL-1994 (Anonymous, AOAC (1984). a Technicon amino acid ana- The dietary value of P. m a - 1994). In addition, more re- lyzer model NC2P (Technicon ximartinezii results favorable cently Ledig et al. (1999) Fatty acid analysis International, Geneva). Tryp- when compared with some based on allozyme frequencies, tophan was isolated by enzy- commercial nuts. For instance, alleles per locus, and gametic Fatty acid methyl esters matic hydrolysis with pepsin pecan (Carya illinoensis) con- disequilibrium measures for were analyzed by gas-liquid and panchreatine reaction for tains 9-10% crude protein, 71- nine major polymorphic loci, chromatography (GLC). Sam- 24h. A hydrolysate aliquot was 73% fat, and 11-15% carbohy- have shown that P. maximar- ples were injected into a Hew- made to react with p-dimethyl- drate; peanut (Arachis hypo- tinezii may have survived an lett-Packard HP 5890 gas aminobenzaldehyde and the gaea) contains 26% crude pro- extreme bottleneck. chromatograph (GC), with a product was quantified with a tein, 39% fat, and 24% car- flame ionization detector (FID) spectrophotometer at 590 nm bohydrate; cashew (Anacar- Materials and Methods coupled to an electronic inte- and standard Tryptophan curve dium occidentale) contains grator. The GC was equipped (Lucas and Sotelo, 1980; Ras 17.2% crude protein, 45.7% Cones of P. maximartinezii with a 60-m SP-1000 capillary et al., 1974). fat, and 29.3% carbohydrate; were harvested directly from column (0.25mm ID, µm film while English walnut (Ju- more than 50 randomly se- thickness). The oven was pro- Results and Discussion glans regia) contains 15% lected mature trees. Cones grammed as follows: 60ºC to crude protein, 68% fat, and were dried in open sunlight for 220ºC at 20ºC/min. The final Proximate analysis 12% carbohydrate (Botkin two to three weeks. Then, 250 oven temperature was main- and Shires, 1948; Duke, 1989; cones were randomly selected, tained for 10 min. The injector Table I shows the proximate Lanner, 1981). Therefore, the broken down and cleaned up to and detector temperatures were analysis of P. maximartinezii dietary and biological value of collect complete seeds. In the both 220ºC. Fatty acid methyl nuts along with other nine ed- blue pine proteins exceeds that laboratory, seeds were cleaned, esters were identified by com- ible pine species. Nut compo- of commercial nuts. mixed and stored in airtight paring their retention times to sition varies largely among plastic bags at room tempera- those of pure standard fatty different pine species. P. maxi- Amino acid analysis ture. Nuts were carefully frac- acid methyl esters. Fatty acid martinezii contains one of the tionated in small pieces, stored methyl esters were quantified highest protein values among Just as valuable as the pro- in glass containers at 4°C, and according to their percentage all other pine nut species, ei- tein content is the protein samples of 250g were taken for area obtained by integration of ther crude protein (31.3%) or quality of P. maximartinezii, analyses. peak areas. defatted protein (65.6%). It is largely determined by the

608 DEC 2001, VOL. 26 Nº 12 TABLE II quite important in the Mexi- acids, as well as acids with

AMINO ACID COMPOSITION OF TOTAL can diet which is based Carbon chains larger than C20 SEED PROTEINS IN Pinus maximartinezii NUTS mainly on corn. In this re- (Table III). The most abundant spect, the essential amino ac- fatty acids in blue pine are the P. maximartinezii FAO/WHO ids of blue pine nuts compare unsaturated linoleic and oleic g/16 g N g/100 g g/16 g N relatively well with the levels acids, which comprise about Amino acid sample* suggested by the FAO/WHO 84% of the total fatty acids. (1990, Table II). Studies conducted by Yoon et Methionine* 1.95 1.27 2.5 A single-source protein sel- al. (1989), and Han and Tryptophan* 0.57 0.37 1.1 dom serves independently as a Hwang (1990) on P. koraien- Lysine* 2.64 1.73 5.8 source of dietary amino acids. sis, revealed relatively high Leucine* 9.18 6.01 6.6 It works in concordance with levels of the unsaturated oleic Isoleucine* 4.41 2.89 2.8 other equally important pro- and linoleic acids, which com- Phenylalanine* ξ 2.88 1.88 – teins. Hence, the most impor- prise about 73% of the total. Valine* 4.60 3.02 3.5 tant characteristic of each pro- Sagrero-Nieves (1992) work- Threonine* 2.16 1.41 3.4 tein in the diet is its ability to ing on three different seed Histidine* 2.06 1.35 – fill the gaps between the quan- coat phenotypes of P. cembroi- Cysteine 1.80 1.18 – tities of essential amino acids des from Mexico also quanti- Tyrosineξ 4.22 2.76 6.3 needed and those supplied by fied high levels of both oleic Total Aromatics 7.10 4.64 – other foods. When examined and linoleic acids, which ac- Total Sulphured 3.75 2.45 – from this standpoint, blue pine counted for about 82% of total Aspartic acid 10.43 6.83 – nut proteins appear to be more fatty acids. Likewise, Lanner Glutamic acid 10.75 7.05 – valuable as a source of supple- (1981) reported that unsatur- Glycine+Alanine 9.26 6.07 – mentary proteins. Blue pine ated fatty acids from P. edulis Proline 2.78 1.82 – nut is deficient in Methionine, and P. monophylla are the Serine 5.66 3.71 – Lysine, Tryptophan, and possi- oleic, linoleic, and linolenic Arginine* 16.73 10.96 – bly Threonine. Such an essen- acids, which altogether ac- tial amino acid limitation must count for about 85% of the to- (* = essential amino acids; ξ = aromatic amino acids). be considered when blue pine tal. nut proteins are added for nu- The essential unsaturated li- amino acid composition and Glutamic acids, as well as tritional purposes. It is there- noleic acid content in P. digestibility of the protein. Glycine, Alanine, Serine, and fore necessary to supplement maximartinezii is high as The importance of essential Proline, all of which surpass blue pine proteins with these compared with that of P. cem- amino acids in the diet is em- those of Korean pine. amino acids when they are the broides and P. koraiensis. Li- phasized in several studies, Studies by Massieu et al. sole source of protein. Alterna- noleic acid is of biological further supported by the Inter- (1950) have indicated that tively, blue pine proteins can importance for the biosynthe- national Committee of FAO/ Lysine, Tryptophan, and Me- be blended with proteins from sis of arachidonic acid (not WHO (1990). Eighteen of the thionine are limited in the other oilseed proteins, le- present in plants), and the ab- twenty amino acids are found Mexican diet, specially in the gumes, and cereals to provide sence of these two fatty acids in nut protein of blue pine poorest people living in the a good amino acid balance. in the diet may result in cer- (Table II), as in Korean pine rural country. Besides its role tain pathological conditions, (Han and Hwang, 1990), while as one of the limiting essen- Fatty acid analysis and eventually death, in ex- all twenty are present in P. tial amino acids in protein perimental animals (Len- edulis and P. monophylla metabolism, Tryptophan is a P. maximartinezii nuts con- ninger, 1975). The total fatty (Lanner, 1981). The nutritional precursor for the synthesis of tain palmitic, stearic, oleic, li- acids found in nuts of P. value of blue pine nuts lies the neurotransmitter serotonin noleic, arachidic, and behenic maximartinezii also suggest partly in the fact that all es- and Tryptamine, as well as sential amino acids such as for the synthesis of the anti- Arginine, Methionine, Tryp- pellagra vitamin nicotinic acid TABLE III tophan, Lysine, Leucine, Iso- and the epiphyseal hormone FATTY ACID COMPOSITION OF Pinus maximartinezii leucine, Phenylalanine, Valine, melatonin (Heine et al.,1995). Threonine, and Histidine are Tryptophan and its metabo- Fatty acid Nut dry present in significant concen- lites regulate neurobehavioral weight (%) trations, above 1% (Table II). effects such as appetite, sleep- In contrast, in Korean pine ing-walking-rhythm and pain Palmitic C16:0 8.74 only Arginine, Aspartic acid, perception. Although these Stearic C 3.97 Glutamic acid, and Methionine three essential amino acids 18:0 Oleic C18:1 31.35 content surpass 1% (Han and are found in blue pine nuts, Linoleic C 52.27 Hwang, 1990). they occur in relatively low 18:2 Arachidic C20:0 0.47 All ten essential amino ac- percentages. Nevertheless, Behenic C 0.40 ids but Tryptophan are found blue pine nut is exceptionally 22:0 Larger than C 2.80 in nuts of blue pine (Table II) rich in protein and contains a 20 in relatively high percentages high proportion of essential as compared with that of P. amino acids, including Argin- Total saturated 16.38 koraiensis and contains high ine, Leucine, Isoleucine, and Total unsaturated 83.62 percentages of Aspartic and in a lesser extent Valine, all

DEC 2001, VOL. 26 Nº 12 609 that they are of high food the current population growth. ACKNOWLEDGEMENTS Lanner RM (1981) The Piñon Pine. quality, similar to that re- P. maximartinezii is an en- A Natural and Cultural His- tory. University of Nevada ported for P. cembroides, P. demic and threatened species The author thanks Teresa Press, Reno. Nevada. 101 pp. edulis, P. koraiensis, and P. because of its small popula- Terrazas and Edmundo Ledig TF, Thompson M, Bermejo- monophylla. However, based tion size, extremely restricted García-Moya for their useful Velázquez B, Eguiluz-Piedra T, on unsaturated fatty acids distribution and its habitat comments to an earlier manu- Hodgskiss PD, Jonson DR, content alone, nuts from P. conversion, which is directly script. Financial support was Dvorak WS (1999). Evidence for an extreme bottleneck in a maximartinezii are of similar associated to recent land-use provided by the National rare mexican pinyon: genetic quality than those of P. edulis changes resulting in a reduc- Commission for the Knowl- diversity, disequilibrium, and and P. monophylla, and higher tion of its natural range, soil edge and Use of Biodiversity the mating system in Pinus than P. koraiensis and P. erosion and habitat fragmenta- (CONABIO) contract FB305/ maximartinezii. Evolution 53: pinea. Blue pine unsaturated tion. Other factors, such as H140. Chemical analyses 91-99. fatty acids, moreover, are the overgrazing and induced were carried out in the Lenninger AL (1975) Biochemistry. 2nd edition. Worth Publishers higher than some commercial forest fires, which result in Laboratorio de Química Inc. New York. 1104 pp. nuts like pecans (73%), En- prevention of recruitment of Analítica at the Facultad de Little EL, Critchfield WB (1969) glish walnuts (68%), and pea- seedlings and saplings and the Química, UNAM. Subdivisions of the genus nuts (29%) (Botkin and current seed over harvesting Pinus (Pines). Miscellaneous Shires, 1948; Lanner, 1981). and illegal trade also threat Publication 1144. Forest Ser- REFERENCES vice, USDA, Washington DC, From an ecological stand- the long-term persistence of USA. 51 pp. point, P. maximartinezii en- blue pine. Levels of seed har- Lucas B, Sotelo A (1982) Amino ergy, primarily stored in form vesting must be investigated Anonymous (1994) Norma Oficial acid determination in pure pro- of proteins, lipids, or carbo- because they may prevent Mexicana NOM-059-ECOL- teins, foods and feeds using hydrates (either starches or natural regeneration and, in 1994. Diario Oficial de la two different hydrolysis meth- Federación. pp 35-45 ods. Anal. Biochem 123: 349- sugars) may be crucial very the long-term, forest growth. 356. early in its life-history. For Research in that direction is AOAC (1984) Official Methods of Analysis. 14th edition. Associa- Lucas B, Sotelo A (1980) Effect of instance, nut energy allocation being conducted to evaluate tion of Official Analytical Che- different alkalies, temperatures to roots, stem, and cotiledon- the maximum level of seed mists. Washington, DC. 501 pp. and hydrolysis times on tryp- ary leaves, may be quite criti- harvesting that warrants popu- Botkin CW, Shires LB (1948) The tophan determination in pure cal, during the seedling estab- lation stability. Blue pine rep- composition and value of proteins and foods. Anal. Biochem 109: 192-197. lishment phase, in determin- resents, therefore, a good op- piñon nuts. New Mexico Agric Exp Stn Bull 344. pp. 3-14. Martínez M (1948) Los Pinos ing seedling growth rates just portunity to conciliate conser- nd Crawford M (1995) Nut pines. Mexicanos (2 ed). Ediciones before becoming self-sustain- vation values with manage- Yearbook Western Australian Botas, México City, D.F. 361 ing, as it is for most long- ment and economic develop- Nut and Tree Crops Associa- pp. lived plants (Fenner, 1987; ment. tion 19: 56-66. Massieu GH, Guzmán J, Cravioto Harper, 1977). Although seed Donahue JK, Mar-López C (1995) RO, Calvo de la Torre J Observations on Pinus maxi- (1950) Contenido de aminoáci- energy of P. maximartinezii is Conclusions dos indispensables en algunas relatively high as compared martinezii Rzed. Madroño 42: 19-25. semillas mexicanas. Ciencia with other pine species, the The large edible nuts of P. 10: 142-144. Duke JA (1989) CRC Handbook of Perry JP (1991) The Pines of ecological importance of the maximartinezii are of out- Nuts. CRC Press. Boca Raton, amount of energy stored in standing dietary value as Florida. 368 pp. Mexico and Central America. Timber Press. Portland, Or- the nut will depend, however, compared with other pinyon Duke JA, Atchley AA (1986) CRC egon. USA. 231 pp. Handbook of Proximate Analy- on the form in which it is pine species and commercial Ras RMV, Tara MR, Krishnan CK sis Tables of Higher Plants. packed and mobilized. It is nuts. They are a remarkable (1974) Colorimetric estimation CRC Press. Boca Raton, of tryptophane content of known that lipids, for in- source of protein, essential Florida. pp. 130,332. pulses. J. Food Sci. Technol. stance, contain more energy amino acids and unsaturated FAO/WHO (1990) Protein quality per unit weight than carbohy- fatty acids for human nutri- 11: 213-216. evaluation. In Report of a Joint Rzedowski J (1964) Una nueva drates (starches) but they are tion. However, the utilization FAO/WHO Expert Consulta- especie de pino piñonero del more slowly mobilized. Like- of seeds needs to be thor- tion. Food and Agriculture Or- Estado de Zacatecas (México). wise, sugars are more readily oughly evaluated since species ganization of the United Na- Ciencia 23: 17-20. tions, Rome, Italy, p 23. available than starches. On management may be hindered Sagrero-Nieves L (1992) Fatty acid Farjon A, Styles BT (1997) Pinus composition of Mexican pine the other hand, predator-dis- by the lack of basic ecologi- (Pinaceae). Flora Neotropica perser animals like squirrels cal research. Sound manage- nut (Pinus cembroides) oil Vol. 75. The New York Botani- from three seed coat pheno- and birds, tend to prefer large ment proposals for P. cal Garden, New York. pp. types. J. Sci. Food Agric. 59: seeds, but quantifying the size maximartinezii require a com- 221-224. 413-414. effect is complicated due to prehensive perspective on Fenner M (1987) Seedlings. New Styles BT (1993) Genus Pinus: a variation in seed abundance conservation and develop- Phytol. 106: 35-47. Mexican Purview. In (specially for mast-seeding ment, and an integrated ap- Han SS, Hwang BH (1990) Analy- Ramamoorthy TP, Bye R, Lot sis of amino acid, fatty acid, A, Fa J (Eds) Biological Di- trees) besides nut nutritional proach to decision-making. and vitamin in Korean pine versity of Mexico: Origins and quality and the identity of the Such proposals should take (Pinus koraiensis) seeds. J. Distribution. Oxford University predator-disperser vector (Th- into account an integrated re- Korean For. Soc. 79: 345-351. Press. New York. pp 397-420. ompson, 1987). search of the social, economi- Harper JL (1977) Population Biol- Thompson K (1987) Seeds and Before any management cal, and political aspects lo- ogy of Plants. Academic Press, Seed Banks. New Phytol. 106: plans are implemented for cally involved, all of them fo- Orlando, Florida. 892 pp. 23-34. Heine W, Radke M, Wutzke KD Yoon TH, Im KJ, Koh ET, Ju JS this species, it is necessary to cusing on protecting the spe- (1995). The significance of (1989) Fatty acids composition take into account the potential cific habitat where this en- tryptophan in human nutrition. of Pinus koraiensis seeds. impact of seed harvesting on demic rarity occurs. Amino acids 9: 191-205. Nutr. Res. 9: 357-361.

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