Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1951 L37 / Master of Science

Cupuassu (Theobroma grandiflorum), one of the most profitable crops of Amazonia, is now attracting world-wide attention as an exotic fruit, used in juices, ice cream and sweets. It is a shade tolerant tree that can be grown as a component of agroforestry systems. Nevertheless it is still a wild species and little is known about its biology. Floral biology of cupuassu was studied in Belem-Brazil during 2 floweringfruiting seasons between June 1991 and December 1993. Flowering occurs in the drier period of the year. Flowers commence opening at any time of the day, but open fully at the end of afternoon. The anthers dehisce and the stigmas are receptive as soon as the flowers are fully open. Stigmas remain receptive until 10:00 am the following day. Throughout this period, the pollen grains remain viable. The flowers have a complex morphology which favours allogamy. The species is also self-incompatible. Experimental pollinations, using compatible pollen grains, have shown that a flower which receives 60 compatible pollen grains has 20% probability of setting fruit; a flower which receives more than 400 pollen grains always sets fruit. However, only around 2% of naturally pollinated flowers receive more than 60 pollen grains. A stingless bee, Plebeia minima, is considered an effective pollinator of cupuassu. Another stingless bee, Trigonisca pediculana, also visits cupuassu flowers. Both bees are small insects, which are unlikely to fly very far. Ants (Wasmannia sp.) and weevils (Baris sp.) were considered secondary pollinators, unlikely to promote effective pollinationsFruits mature during the wet period of the year, approximately 5.5 months after the flowers open. The limited and irregular fruit set is probably caused by scarcity of pollinators. The transformation of cupuassu to a plantation crop will therefore require conditions which favour natural pollinators and their access to receptive and compatible flowers

A dissertation of published papers submitted by the author for the degree of Doctor in AgricSciences / Thesis (DSc)--Stellenbosch University, 1983. / ENGLISH ABSTRACT: No abstract available / AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar

Response Surface Methodology (RSM) was used to study the effect of two variables, sugar level (12-16 °Brix) and acid level (0.3-0.7 % T.A.) on sensory qualities and desirability of blackberry juice drinks. Three blackberry juice levels (10%, 15%, and 20%) were used to study the influence of juice flavor on sensory qualities and desirability of the juice drinks. A trained panel evaluated three attributes, blackberry flavor, sweetness, and sourness intensities, of the juice drinks. The consumer panel gave desirability and three attributes just-right ratings. A Balanced Complete Block Design was used. Blackberry flavor intensity was enhanced by sugar level. Blackberry flavor intensity was enhanced by acid level to a point about 0.5% T.A., and then decreased. Blackberry flavor intensity was not related to °Brix:acid ratio and was only related to the sweetness:sourness ratio at the 20% juice level. Sweetness and sourness intensities increased with increasing sugar and acid levels. There was a suppression effect of sugar and acid on each other in the juice drink. The relationships of sweetness, sourness, and sweetness:sourness ratios to °Brix:acid ratios were all linear. Desirability rating was related to °Brix:acid and sweetness:sourness ratios for the 10% and 20% juice levels, for 15% juice level no association was found. The formula which received the closest to "just right" ratings and highest overall desirability rating had in a °Brix of 15.4 and a % titratable acidity of 0.64, resulting in a °Brix:acid ratio of 24 and a corresponding sweetness:sourness ratio of slightly less than 1.0. In general, the 15% juice level was the best because of its sugar and acid tolerance and high desirability. / Graduation date: 1989

It has long been recognized that fermented food products possess a characteristic but pleasant flavor. The use of such foods, however, has been limited by the presence of ethanol. Thus the objective of this research was to investigate the possibility of producing non-alcoholic fermented juice concentrates. Three varieties of juices, Concord grape, apple, and blackberry, were ameliorated as needed and fermented to five to seven percent alcohol by volume. The fermented flavor was extracted with ethyl chloride and concentrated by distillation. These extracts were analyzed by gas chromatography using two different column temperatures. Low column temperature was 100°C while high column temperature was 170°C. Four peaks were found to contribute from 93 to 97 percent of the flavor compounds chromatographically separated from the three juices at low temperature. By use of the enrichment technique, these peaks appeared to be propyl alcohol, isobutyl alcohol, butyl alcohol, and a mixture of isoamyl and active amyl alcohol. At high temperature separation, four peaks were observed to comprise 56 to 64 percent of the flavor components fractionated. These four peaks appeared to be a mixture of acetic acid and ethyl octanoate, caproic acid, phenethyl alcohol and caprylic acid. Other components were tentatively identified to be acetone, ethyl acetate, ethanol, n-amyl alcohol, ethyl hexanoate, n-hexanol, propionic acid, 2, 3-butylene glycole, butyric acid, isovaleric acid, diethyl succinate, 4-butyrolactone, valeric acid and capric acid. Freeze drying and a combined method of distillation and freeze centrifugation were the two methods employed to remove ethanol and water from the fermented juices. A fivefold concentration of the original juices was obtained. From 91 to 95 percent of the alcohol and 80 percent of the water were removed from the juices by freeze drying while the combined technique removed only 79 percent of the ethanol and 80 percent of the water. Total acids, color and total soluble solids were not affected by the freeze drying procedure whereas the combined technique for removal of the alcohol resulted in some loss of these constituents. The fermented dealcoholized juices were analyzed by gas chromatography using only high temperature columns. These data indicate that dealcoholization resulted in a decrease in the peak heights of the first ten peaks to be separated. The remainder of the peaks generally showed an increase although a few exceptions were noted. The dealcoholized fermented juice concentrates were reconstituted and evaluated by a flavor panel. The panel data indicated that the rank order of preference for the three juices was blackberry, apple and Concord grape. The flavor panel also preferred the juices served at the higher levels of sweetness. The total average panel score for these three juices was observed to be about a neutral rating of "neither like nor dislike". / Graduation date: 1966

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7 pp. / This publication discusses some backyard fruits that can be grown at elevations between 3500 to 6000 feet and also lists varieties of each fruit by harvest season.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.