APPLICATION OF THE PRINCIPLES OF JELLY 
MAKING TO HAWAIIAN FRUITS. 
CONTENTS. 
Page. 
Introduction 1 
Methods 1 
The guava for jelly making 4 
Effect of varying proportions of sugar, pec- 
tin, and acid in jelly making 9 
Page. 
Other Hawaiian fruits for jelly making 14 
Consistency of jellies as affected by the physi- 
cal properties of pectin 22 
Summary 23 
INTRODUCTION. 
Although tropical fruit products have been given wide publicity 
within recent years and there is an ever-increasing demand for them 
on the world markets, jelly making from tropical fruits remains as 
yet a comparatively undeveloped industry. Probably the only 
two tropical fruit jellies of any commercial importance at the present 
time are those made from guava (Psidium guayava) and poha (Physalis 
peruviana). Guava jelly, owing to the comparatively small cost of 
production and the growing of the wild fruit in abundance, is the 
standard jelly as well as the basic product of the fruit jelly industry 
in Hawaii. Poha jelly production is as yet small, owing to the 
limited supply and high cost of the fniit. Since the exportation 
in the fresh state of many Hawaiian fruits is prohibited by quarantine 
regulations, the fruit jelly-making industry in Hawaii should serve 
as a stimulus for producing and exporting Hawaiian fruit products 
in greater abundance than is now the case. 
Extensive studies have been made of, and formulae developed for, 
the making of jellies from every important fruit of the Temperate 
Zone, but little or no study has been devoted to the making of jelly 
from fruits from the Tropics. The writer, therefore, made an ex- 
haustive study of the Hawaiian guava for jelly making for the 
purpose of developing a systematic procedure by means of which 
jelly may successfully be made from any kind of jelly fruit. 1 This 
ulletin gives the results of the investigation. 
METHODS. 
A review of the different studies on jelly making showed that 
there are no generally accepted methods for conducting a systematic 
study of the jelly-making qualities of a fruit, and that the tendency 
is to develop formulae for different fruits rather than general prin- 
ciples which will apply to all jelly fruits. The methods followed 
by the writer require little time and simple apparatus, and while 
the results obtained from their use can not be considered in the 
light of accurate quantitative results, they are, it is thought, suffi- 
ciently accurate for a practical study of jelly making. 
1 A fruit containing the essential constituents for jellying, i. e., pectin and acid. 
i 6 
