Novel aroid products

Novel products are prepared from Aroid corms by first peeling and washing the corms and then cutting the corms into pieces. Aqueous alkali is applied to the corms to remove acid principles and then the corms are treated with aqueous hydrogen peroxide to prevent discoloration. The so-treated corms are washed with water until they are neutral and then dried.

BACKGROUND OF THE INVENTION 
1. Field of the Invention: 
This invention relates to and has among its objects novel products from 
Aroids (family Aracae) and novel methods of making the same. It is a 
particular object of the invention to reduce the acridity and 
decolorizability of Aroid material. Further objects of the invention will 
be evident from the following description wherein parts and percentages 
are by weight unless otherwise specified. 
2. Description of the Prior Art: 
Aroids (family Aracae) possess a corm, or a rounded thick modified 
underground stem base bearing membranous or scaly leaves and buds and 
acting as a vegetative reproductive structure in certain monocotyledonous 
plants, which may be prepared for human consumption. The most noted of the 
Aroids is taro, an important food crop in tropical and subtropical 
regions. To prepare taro corms for eating complicated cooking procedures 
are required because the corms contain acrid matter that produces 
irritation of the mucous membranes in the mouth and throat. The cooked 
product from taro called poi is very sticky and viscous and has a high 
moisture content. Consequently, poi is difficult to handle, dry, and 
store, thus, limiting its usefulness as a food. Only the surface of poi 
becomes dried under drying conditions and the dried material is unevenly 
colored. The cooling techniques involve pressure cooking in a retort for 
several hours, peeling, trimming, washing, and grinding; it is notable 
that ordinary cooking techniques, e.g., cooking in boiling water, are 
ineffective in preparing taro corms for consumption. 
SUMMARY OF THE INVENTION 
The invention described herein provides means for avoiding the problems 
outlined above. As a result of the method of the invention novel taro 
products can be obtained simply without resort to complicated processing 
techniques, particularly retorting for extended periods, heretofore 
required. The benefits of the invention are obtained by first peeling and 
washing the aroid corms. Then, the corms are cut into pieces, treated with 
alkali, and then washed to remove the alkali. Next, the corms are mixed 
with water containing hydrogen peroxide and then removed and dried. The 
alkaline solution after removal of the corms can be acidified to yield a 
gum-like substance useful as a thickening or smoothing agent. 
The new products have the advantage of being dry and non-hydroscopic. Thus, 
they are easily stored and transported because, unlike poi, they require 
no refrigeration. Furthermore, they are easily prepared for consumption by 
simple cooking in boiling water for short periods. 
Another advantage of the instant products is that they do not irritate 
mucous membranes in the mouth and throat. Thus, they are not subject to 
the unpleasantness associated with poi and other aroid products. 
Another advantage of the invention is that it allows production of a gum 
from Aroids, which is useful as an emulsifying, thickening, and smoothing 
agent for creams, suspensions, and other colloidal food materials. 
A further advantage of the invention is that it reduces discoloration of 
the Aroid material. As a result, the products of the invention have an 
attractive appearance. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The invention will next be described in detail with emphasis on novel 
products and methods for making them from the taro plant (Colocassia 
esculenta). It should be understood that this emphasis is by way of 
illustration and not limitation. In its broad ambit, the invention may be 
applied to all Aroids (family Aracae) including Colocasia esculenta, 
Alocasia macrorrhiza, Xanthosoma, Schizmatoglottis calyptrata, Cyrtosperma 
chamissonis, Amorphophallus campanulatus, and the like. 
In a practice of the invention taro corms are peeled, washed and cut into 
pieces of any geometrical shape such as cubes, squares, rectangules, etc. 
Typically, the pieces have the following dimensions: cubes, about 10 
millimeters (mm); squares, about 20.times.20.times.2 mm; rectangules, 
20.times.10.times.2 mm. However, as a general rule the size of the pieces 
can vary but should not be so small as to lose their integrity during the 
process of the invention nor so large as to render the instant method 
ineffective. 
The taro pieces are next extracted with an aqueous alkaline agent, such as 
sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like, 
which is non-poisonous. Usually, the concentration of alkaline agent is 
about 2 to 5%, based on the weight of taro corms. The alkaline mixture is 
allowed to stand at room temperatue (about 20.degree. C.) for a period of 
about 10-24 hours or a period of time sufficient to remove the acrid 
principles from the taro. It is within the scope of the invention to 
conduct the alkaline treatment within the temperature range of about 
20.degree.-30.degree. C. 
Following this alkaline treatment the taro pieces are separated from the 
alkaline extract and washed with water to remove the alkaline agent. The 
pH of the taro pieces should be about 9-10. 
The so-extracted pieces are mixed with water in the ratio of 2-4 parts of 
water per part of taro. Then, sufficient food grade hydrogen peroxide is 
added such that the final concentration of hydrogen peroxide in the water 
is about 0.7-10% based on the weight of taro. Alternatively, the hydrogen 
peroxide can be mixed with water prior to combination with the taro 
pieces. In general, the concentration of hydrogen peroxide should be 
sufficient to decolorize the taro. For practical purposes the treatment 
with hydrogen peroxide is conducted at ambient (room) temperature although 
temperatures in the range of 20.degree.-30.degree. C. can be employed. 
The treatment with hydrogen peroxide is carried out for a period sufficient 
to decolorize the taro. Usually, this occurs after a period of about 10-30 
hours. Whether the decolorizing procedure has been effective can be 
determined by placing a piece of treated taro into boiling water. Absence 
of darkening on the surface of the taro piece indicates that the 
decolorization is completed. 
After treatment with hydrogen peroxide, the pieces are separated and washed 
with water until the pH of the taro is neutral, i.e., about 6.5-7.5. 
Alternatively, the separated pieces can be washed and then allowed to 
stand in water until neutral pH is realized. The neutralized pieces are 
separated from the water and dried to a moisture content of about 5-10%. 
The pieces may be dried in air or by the application of heat as, for 
example, in an oven. 
The new taro products of the invention may be stored and/or transported 
without refrigeration. To reconstitute (hydrate) them for consumption they 
may be placed in about 5-10 parts of water per part of dry taro. The 
reconstituted pieces are easily cooked requiring about one hour in boiling 
water and may be included in a number of recipes. If desired, the 
hydration solution may contain vitamins, minerals, and other nutrients, 
which are absorbed into the pieces and retained therein. 
The alkaline extract, after removal of the taro pieces, can be acidified 
with dilute aqueous food grade acid such as hydrochloric acid, sulfuric 
acid, phosphoric acid, and the like. Acid should be added to attain a pH 
of about 3.5-4.5. The precipitate that forms is separated by conventional 
means such as by centrifugation, filtration, etc., and then dried as 
described above. The dried material swells in water and becomes highly 
hydrated to form a gum that can be used as an emulsifying, thickening, and 
smoothing agent in food preparations. 
The process of the invention may be applied to partially cooked taro corms 
as well as uncooked. It is, therefore, the intent of this disclosure to 
include such a variation within the scope of the present method.

EXAMPLES 
The invention is further demonstrated by the following illustrative 
examples. 
EXAMPLE 1 
Ten grams of uncooked taro corms were peeled and cut into small cubes, 1 
cubic centimeter, and then were mixed with 20 ml of 0.25 N sodium 
hydroxide in a 150 ml jar. The jar was stoppered and allowed to stand at 
room temperature for 24 hours. The cubes were removed from the jar and 
washed with water several times. Then, the cubes (pH 9) were transferred 
to another jar containing 20 ml of water. To the jar was added 0.17 g of 
hydrogen peroxide (100%). The jar was stoppered and the contents were 
allowed to stand at room temperature for 10 hours or more. The cubes were 
removed from the jar and washed several times with water. The cubes were 
then suspended in water with stirring and held for a period of 2 hours, 
this process being repeated until the pH of the cubes was about 7.0. 
The above procedure was repeated except that a 1.0 N sodium hydroxide 
solution was used in place of the 0.25 N solution. 
The so-prepared cubes were separated and dried in air to a moisture content 
of 10%. The dried cubes were rehydrated by suspension in water (50 ml) and 
then cooked. The cooked taro pieces did not discolor and did not irritate 
mucous membranes in the mouth and throat when eaten. 
EXAMPLE 2 
The procedure of Example 1 was followed with the exception that the amount 
of hydrogen peroxide used was 0.14 and 0.07 g, respectively. The cooked 
taro cubes exhibited the same properties as those prepared in Example 1. 
EXAMPLE 3 
Two grams of taro slices (dark brown) heated for 10 minutes in boiling 
water mixed with 10 ml of water in a 150 ml flask. To the flask was added 
10 ml of 0.25 N sodium hydroxide solution. The flask was loosely stoppered 
and allowed to stand at room temperature for one hour. The slices were 
removed from the alkaline solution and rinsed with water. The slices were 
mixed with 15 ml of water in a 150 ml flask and 0.10 g of hydrogen 
peroxide was added to the flask. The flask was loosely stoppered and 
allowed to stand at room temperature for 24 hours or more. 
Another test was conducted in the same manner as above except that 0.20 g 
of hydrogen peroxide was used. 
The so-prepared slices did not irritate mucous membranes in the mouth and 
throat when eaten and were not discolored. 
EXAMPLE 4 
The sodium hydroxide extract from Example 1, after removal of the taro 
cubes, was acidified to pH 4.0 by addition of hydrochloric acid. The 
precipitate that formed was separated by centrifugation and then dried to 
a moisture content of 10%. 
The precipitate was hydrated in water (20 ml) to yield a gum-like 
substance, which may be used as a thickening agent in food preparations.