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European Journal of Applied Sciences – Vol. 12, No. 4

Publication Date: August 25, 2024

DOI:10.14738/aivp.124.16923.

Tersoo-Abiem, E. M., Abel, C. O., & Akpensuen, M. S. (2024). Quality Assessment of Mature Unripe Pawpaw (Carica papaya)

Fruit Powder as a Stabilizer in Thermized Yoghurt. European Journal of Applied Sciences, Vol - 12(4). 124-137.

Services for Science and Education – United Kingdom

Quality Assessment of Mature Unripe Pawpaw (Carica papaya)

Fruit Powder as a Stabilizer in Thermized Yoghurt

Tersoo-Abiem Evelyn Mnguchivir

Department of Food Science and Technology Joseph

Sarwuan Tarka University Makurdi Nigeria

Abel, Christopher Omale

Department of Food Science and Technology Joseph

Sarwuan Tarka University Makurdi Nigeria

Akpensuen Mfe Samuel

Centre for Food Technology and Research (CEFTER),

Benue State University Makurdi

ABSTRACT

Pawpaw fruit powders were produced from two mature unripe Carica papaya fruit

cultivars via sun-drying and oven drying respectively, and were used to stabilize

thermized yoghurt, at 0, 1, 2 and 3% concentrations respectively. The pawpaw

fruit powders were evaluated for functional, physicochemical and microbial

quality. The values for pH, TTA, TSS and moisture content ranged from 5.51±0.01

to 5.71±0.01, 0.11±0.01 to 0.13±0.01, 2.41±0.01 to 2.91±0.01 and 13.35 ±0.21 to

14.90±0.14 respectively. The functional properties of the fruit powders revealed

bulk density, water absorption capacity, oil absorption capacity, emulsion capacity

and foam capacity values ranged from 0.46±0.01 to 0.76±0.01, 0.81±0.01 to

1.61±0.01, 0.81±0.01 to 2.60±0.01, 4.70±0.07 to 7.95±0.07 and 39.21±0.01 to

48.05±0.07 respectively, while the microbial load of the powders were within

acceptable levels. Results of the physicochemical analyses of thermized yoghurt

with addition of pawpaw powder at different concentrations for pH, total soluble

solids, specific gravity and TTA values ranged from 5.39±0.01 to 5.67±0.02,

11.72±0.03 to 12.61±0.01, 1.00±0.00 to 1.19±0.00 and 0.01±0.00 to 0.21±0.01. The

microbial load of the stabilized thermized yoghurt showed no significant bacterial

and fungal count. Results of sensory analyses revealed that 1% pawpaw fruit

powder addition to thermized yoghurt was the most preferred.

Keywords: Stabilizer, thermized yoghurt, unripe pawpaw

INTRODUCTION

Pawpaw (Carica papaya) is a common but seasonal fruit in Nigeria [1]. According to Okon et

al. [2] and Kandasamy et al. [3] pawpaw is a climacteric plant which is prevalent throughout

tropical and subtropical regions around the world, with Nigeria being the leading producer in

Africa. It is a rich source of several antioxidants (vitamin C, vitamin A and vitamin E), minerals

(magnesium and potassium, copper and zinc), B-vitamins (pantothenic acid and folate) and

fiber [4-5]. Ugbogu et al. [6] described pawpaw as a neutraceutical plant, owing to the wide

range of phytochemicals present in it. Phytochemicals in the fruit include terpenoids,

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Tersoo-Abiem, E. M., Abel, C. O., & Akpensuen, M. S. (2024). Quality Assessment of Mature Unripe Pawpaw (Carica papaya) Fruit Powder as a

Stabilizer in Thermized Yoghurt. European Journal of Applied Sciences, Vol - 12(4). 124-137.

URL: http://dx.doi.org/10.14738/aivp.124.16923

alkaloids, flavonoids, saponins, steroids and carotenoids (zeaxanthan, cryptoaxanthan and β- carotene). The study has also shown the presence of proteolytic enzymes (chymopapain) with

antiviral, antifungal, and antibacterial properties in the fruit.

Ripe pawpaw fruit pulp is usually consumed fresh in slices, in chunks as a breakfast or dessert

fruit, used in the production of jam and nectar, dried into slabs, canned in the form of slices; it

has also been used in preparation of ice cream flavorings, ready to eat fruited cereals among

others [3,7-8]. Nwofe and Agbo, [1] noted the relatively high amount of pectin in pawpaw

fruits which makes it useful as a jelling agent in several processed foods. As reported by Okon

et al. [2], the unripe fruits are harvested, shredded and dried into flakes in some parts of

Nigeria especially among the middle-belt region, to be used as vegetable in soups when leafy

vegetables become scarce, especially in dry season. Among the numerous uses of pawpaw,

there is potential for the pulp to be utilized in yoghurt production, baked foods, juice

flavouring and other products [9]. Despite the several uses of pawpaw fruit highlighted,

considerable post-harvest losses still occur in the fresh fruits, due to its rapid senescence,

resulting in high perishability [10]. Dehydration of the fruits into flakes using sun-drying is a

cheap processing technique that has been reported to maintain enzymes and higher amount

of nutrients and phytochemicals [2]. In a report by Kandasamy et al. [3] conversion of

pawpaw fruit into powder is a good alternative for minimizing post-harvest losses. The fruit

powder has been reported as a source of functional materials [11]

Yoghurt, a highly nutritive cultured milk product fermented through the action of

Lactobacillus bulgaricus and Streptococcus thermophillus is highly consumed by people from

both urban and rural areas globally [12]. Fresh yoghurt is usually maintained at low

temperatures during storage to retard the growth and activity of the fermenting starter

culture and improve its sensory quality. With the erratic power supply during storage,

distribution and retail of fresh yoghurt, the fermenting organisms continue their activity

resulting in highly acidic products with less acceptability, and recovery of stressed

contaminant microorganisms, limiting its shelf life and compromising safety [13-14]. Due to

this limitation, thermization is embraced. Thermization is a heat treatment (or

pasteurization) applied to fermented milk with the aim of retarding the growth of

microorganisms and extending shelf-life [13, 15]. Thermized yoghurt is observed to have low

viscosity, and separation of curd, whey and water (syneresis) [13]. Hence, addition of

stabilizers is important to improve the physicochemical and sensory properties (appearance,

taste and mouthfeel) of thermized yoghurt. Stabilizers are substances which enable the

maintenance of a homogeneous dispersion of two or more immiscible substances in food stuff

[16-17]. Commercial stabilizers such as carboxylmethyl cellulose (CMC), microcrystalline

cellulose (MCC), xanthan gum, corn starch, gelatin, gum Arabic [16] have been used in yoghurt

production. These hydrocolloids interact with the casein network and partially absorb the

free water, improving the water holding capacity of proteins [17]

Recently, there has been increased utilization of locally available food sources to ensure food

security, overcome high cost of importation of raw materials and food additives in food

processing and minimize post-harvest losses. With the increase in exchange rates,

culminating into high cost of commercial stabilizers and finished food products, the

processing of mature unripe pawpaw fruit, which is cheap and readily available, into powder

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European Journal of Applied Sciences (EJAS) Vol. 12, Issue 4, August-2024

for use as a potential natural stabilizer is a promising development in improving the viscosity,

mouthfeel and preventing whey seperation of thermized yoghurt, resulting in a more

acceptable product. The objective of this work was to produce pawpaw fruit powder from two

cultivars of mature unripe fruits and evaluate its stabilizing capacity in thermized yoghurt as

well as its potential use as substitute to known commercial food stabilizers.

MATERIALS AND METHODS

Preparation of Pawpaw Powder

Fresh mature unripe pawpaw fruits from two (2) different cultivars namely; Sunrise solo

(long, pear shaped) and Sunset solo (dwarf, pear shaped) were obtained from the University

farm at University of Agriculture Makurdi, Benue state – Nigeria. Materials used for yoghurt

production were obtained from Modern market Makurdi, namely; full cream powdered milk,

sugar, water, starter culture (Streptococcus thermophilus and Lactobacillus bulgaricus). The

peeled pawpaw fruits were sliced into small pieces after removal of the seeds to an average

thickness of 6mm.The fruit slices from each cultivar were then divided into two portions for

hot air oven drying at 60 °C for 22 hours and sun-drying on a stainless-steel table for 5 days

respectively. The dried slices were then milled using attrition mill, sieved (using 300μm sieve

pore size) and the pawpaw fruit powder obtained was packaged in airtight plastic containers.

The samples were labelled as Sundried sunrise solo papaya cultivar (S1S), Sundried sunset

solo papaya cultivar (S2S), Oven dried sunrise solo papaya cultivar (S1O) and Oven dried

sunset solo papaya cultivar (S2O). Yoghurt was produced following the procedure described

by Balami et al. [18], with slight modifications.

Weighing ingredient (milk, sugar, stabilizer)

Mixing ingredient

Pasteurization (@ 80 °C for 20 minutes)

Colling (to 45 °C)

Inoculation

Incubation (12 hours)

Stirring

Addition of stabilizer (0, 1, 2 and 3%)

Thermization (75°C for 15 minutes)

Bottling

Cooling

Fig. 1: Flow chart for the production of yoghurt

Source: Balami et al, [18] (modified)