Pastries Darkwa and Darkwa (2013) reported processing and sensory evaluation of taro wheat composite chips (pastries). For the preparation of chips, 300 g of margarine and 1 tablespoon of adobo seasoning (salt free) were mixed to 200 g of taro wheat composite flour. Three tablespoons of water were added to form a dough. The dough was rolled into a size of about 0.4 cm in thickness and cut into straw chips. The chips were arranged on a lightly greased baking sheet and baked at a temperature of 180 °C for 12–15 min to golden brown. The score of the taste, colour, flavour and texture of pastries increased as the level of taro increased (20–75 %) in the composite. Only the appearance diminished with increase in taro proportion.
Taro Doughnuts Payne et al. (1941) reported a recipe for preparation of taro doughnuts. The ingredients were 1/2 cup of taro flour, 7/3 cup of wheat flour, 3/2 teaspoon of baking powder, 1/2 cup of sugar, 3/4 teaspoon of salt, 1/8 tea of spoon cinnamon, 1/8 teaspoon of nutmeg, 5/4 tablespoon of shortening, 1 egg and 2/3 cup of milk. In the procedure of preparation, the shortening and half the sugar were creamed. The remaining sugar was added to well-beaten egg and combined with the first mixture. The milk was added, followed by the flour, baking powder, salt and the spices. The dough was then rolled to about 1 cm in thickness and fried in deep fat.
Taro Muffins The following ingredients are used: 3 tablespoons of taro flour, 5/4 cup of wheat flour, 5 teaspoons of baking powder, 1/2 teaspoon of salt, 3 tablespoons of sugar, 1 cup of milk, 2 tablespoons of melted or liquid shortening and 1 egg. All the dry ingredients are combined and sifted twice. The liquid ingredients are also combined, added to dry ingredients which were then mixed enough to dampen flour. The dough was then baked at 205 °C for 35 min (Payne et al., 1941).
Taro Spice Nut Loaf (Payne et al., 1941) The shortening (1/2 cup) and sugar (1 cup) were creamed. Eggs yolks (2 eggs) were well beaten and added to the creamed mixture. The dry ingredients, taro flour (1/4 cup), wheat flour (7/4 cups), baking powder (4 teaspoons), nutmeg (1 teaspoon) and cinnamon (1 teaspoon), salt (1/4 teaspoon) were mixed and sieved twice. The dry ingredients were then added to the creamed mixture alternatively with milk, after which chopped walnuts (1/4 cup), raisins (1/4 cup), the vanilla (1 teaspoon) and folded in egg whites were added and beaten until stiff. The mixture was baked for about 50 min at temperatures varying from 160–190 °C.
Parker House Rolls In the procedure of roll preparation, scalded milk (1 tablespoon), shortening (1 tablespoon), sugar (1 tablespoon) and salt (1/2 teaspoon) were combined and the softened yeast cake (dissolved in lukewarm water) was added. Taro flour (1/4 cup) and wheat flour were added gradually to make a poor batter which was beat until tough and elastic. The remaining flour was added to make a firm dough, turned onto a floured board and kneaded until smooth and no longer sticking to the board. The dough was then placed in an oiled vessel, covered and placed over hot water and allowed to double in bulk for 2.5 h. The sides were loose with a spatula placed on floured board, kneaded and rolled to about 0.5 cm thickness. The dough was lifted from the board and slapped against the board before cutting with a 5–6 cm diameter cutter. Pieces of rolls were creased in middle, brushed half of the circle with melted butter, folded and the edges pinched together, placed on a greased pan, and the top brushed with melted butter. The rolls are kept for 1 h to double in volume before being baked for 13 min at 220 °C.
9.2.3 Snacks
9.2.3.1 Taro Extrudates Snacks
Extrusion cooking is a technology that has been in use since the 1950s and because of its low cost, energy efficiency and high productivity, it has become very popular. Various products are actually produced in industries based on extrusion and these include pasta, meat analogs, puffed snacks, etc. The technology is based on forcing the food material through a barrel at high temperatures and pressures, which pass through a die at the end of the barrel to form the desired shape. Harper (1989) considered the food extruder a high-temperature short-time bioreactor that transforms a variety of raw ingredients into modified intermediate and finished products.
The operations involved in extruders include grinding the food material, mixing, homogenizing, cooking, cooling, vacuumizing, shaping, cutting and filling operations (Riaz, 2000). The quality of the product obtained depends not only on the raw material used, but also on the temperature and pressure conditions, and the type of die used at the end of the channels. In addition, there exist several types of extruders functioning under various conditions (Riaz, 2000) and the choice depends on the type of product needed. The common materials used in extrusion are starchy including cereals, legumes and tubers. Some research works have been undertaken to test the extrusion of taro corm in the preparation of various food.
Taro flour has been the subject of extrusion to obtain various types of snacks. In particular, taro was extruded into noodles by adjustment of dough temperature and moisture content. Mung bean flour or soy protein was added to enrich protein content (Moy et al., 1980). Maga et al. (1993) evaluated the role of extrusion temperature on certain physical properties of taro extrudate. The maximum expansion ratio was found at the extrusion temperature of 120 °C, which was also effective for gelatinization (the water absorption was >500 %). Increasing the extrusion temperature resulted in decreasing extrudate breaking strength. According to the results of Onwulata and Konstance (2001), extrudate from taro flour mixed with whey products expanded more, but absorbed less water and were less soluble than taro alone. The peak viscosities of the blends were lower than for taro flour.
Lee and Hamiday (1997) compared some physicochemical and sensory properties of taro, sweet potatoes and potatoes extrudates. Taro flour was tempered to 16 % humidity and extrudated with an extruder of 1.90 cm diameter, a barrel length to diameter ratio 20: 1 and temperature 120–150 °C. Taro extrudate was lighter as compared to sweet potatoes and Irish potato extrudates. Compared to sweet potatoes, taro extrudate exhibited larger diameter, high expansion ratio, but lower density and breaking strength, which are desirable characteristics in extrudate quality and therefore the taro extrudates makes the more desirable snack. In this respect, the results of the organoleptic evaluation showed that taro extrudate had a higher overall acceptability. In particular, the colour, flavour and crispness of taro extrudate were highly rated.
Nurtama and Lin (2009) studied the effect of process variables on the physical properties of taro extrudate. Extrudates were prepared from taro flour obtained by peeling, slicing, drying at 45 °C and grinding. The dried taro was extruded directly using a collet extruder. Collet extruders are high-shear machines with grooved barrels and screws with multiple shallow flights. These extruders have been used for making puffed snacks from defatted corn grits (Riaz, 2000). In collet extruders, the temperature of dry ingredients (12 % moisture) is raised rapidly to over 175 °C and the resulting mass loses moisture and puffs immediately upon exit through a die to form a crisp, expanded curl or collet. Collet extruders initially were characterized by an extremely short screw (length: diameter = 3: 1), but longer L/D (1: 10) machines that rely heavily on friction-induced heat have been developed. Nurtama and Lin (2009) set up their heater temperature at 120 °C. The cutter speed was in the range of 130–180 rpm. They studied the effect of moisture content of the taro flour (10 and 13 %) and extrusion screw speed (30 and 50 Hz) on the colour, moisture content and density following a 2 × 2 experimental design. After extrusion, the analyzed samples of extrudate showed that the quality of the extrudate varied mostly with the initial moisture content of taro flour, while the extrusion screw speed had only marginal effect.