Unearthing the Potential of the Frafra Potato (Solenostemon Rotundifolius) Flour in Culinary Application: Sensory and Nutritional Analysis of Its Pastry Products

Journal of Culinary Science & Technology

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Unearthing the Potential of the Frafra potato (Solenostemon rotundifolius) Flour in Culinary Application: Sensory and Nutritional Analysis of its Pastry Products

Charles Tortoe, Paa Toah Akonor, Francis Kusi, Peter Asungre Anabire, Robert Kawku Owusu & Constance Boateng

To cite this article: Charles Tortoe, Paa Toah Akonor, Francis Kusi, Peter Asungre Anabire, Robert Kawku Owusu & Constance Boateng (2020) Unearthing the Potential of the Frafra potato (Solenostemonrotundifolius) Flour in Culinary Application: Sensory and Nutritional Analysis of its Pastry Products, Journal of Culinary Science & Technology, 18:1, 1-12, DOI: 10.1080/15428052.2018.1495588 To link to this article: https://doi.org/10.1080/15428052.2018.1495588

Published online: 13 Jul 2018.

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Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=wcsc20 JOURNAL OF CULINARY SCIENCE & TECHNOLOGY 2020, VOL. 18, NO. 1, 1–12 https://doi.org/10.1080/15428052.2018.1495588

Unearthing the Potential of the Frafra potato (Solenostemon rotundifolius) Flour in Culinary Application: Sensory and Nutritional Analysis of its Pastry Products Charles Tortoea, Paa Toah Akonora, Francis Kusib, Peter Asungre Anabirec, Robert Kawku Owusub, and Constance Boatenga aCouncil for Scientific and Industrial Research - Food Research Institute, Food Technology Research Division, Accra, Ghana; bCouncil for Scientific and Industrial Research - Savanna Agricultural Research Institute Crop Protection and Postharvest Department, Manga-Bawku, Ghana; cCouncil for Scientific and Industrial Research - Savanna Agricultural Research Institute, Plant Breeding and Crop Improvement Department, Manga-Bawku, Ghana

ABSTRACT ARTICLE HISTORY Frafra potato is an underutilized crop with enormous potential Received 16 January 2018 as a food security crop. Sensory attributes of bread and koose Revised 17 April 2018 (a traditional Ghanaian pastry) produced from 10 varieties of Accepted 12 June 2018 Frafra potato flour as composite flour and nutritional values KEYWORDS were analyzed. Bread and koose produced from partial substi- Frafra potato; Solenostemon tution of Frafra potato flour were comparable to wholly wheat rotundifolius; sensory flour, especially 20% substitution with variety UW022 for bread evaluation; nutritional and 30% substitution with variety UE021 for koose. Using a 9- analysis; pastry product point Hedonic scale, overall acceptability level was 7.8 for variety UW022 for bread compared to 7.9 for wheat flour, similar to koose. Variety UW022 bread was carbohydrate dense (72.58 g/100 g) whereas variety UE023 bread was richer in ash, fat, protein, crude fiber and energy. Variety UE023 koose at 20% was highest in protein content (20.75 g/100 g) but lower carbohydrates (47.3 g/100 g).

Introduction Frafra potato (Solenostemon rotundifolius Poir) is sometimes referred to as Coleus dysentericus (Tindall, 1983), Coleus rotundifolius (Bejoy, Vincent, & Hariharan, 1990; Mohankumar & Nair, 1990; Vasudevan & Jos, 1992), Coleus parviflorus (Abbiw, 1990; Yayock, Lombin, & Owonubi, 1988). It is white, red or dark-brown tubers mostly cultivated in the Savanna region from Senegal through Western Sudan and some parts of Ghana, Mali, Nigeria and South Africa (Nkansah, 2004). In Ghana, Frafra potato is mainly grown in the Guinea and Sudan Savanna agroecological zones. It is an underutilized crop, grown for domestic consumption contributing approximately 20% of household food between

CONTACT Charles Tortoe [email protected] Council for Scientific and Industrial Research - Food Research Institute, Food Technology Research Division, P. O. Box M20, Accra, Ghana Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/wcsc. © 2018 Taylor & Francis 2 C. TORTOE ET AL.

October and December (Sugri, Kusi, Kanton, Nutsugah, & Zakaria, 2013). Often, yields of the Frafra potato range between 5 and 15 t/ha when envir- onmental and planting conditions are good. Traditionally, it is boiled, roasted, fried or steamed before consumption. Frafra potato is a good source of nourishment as it contains significant amounts of macro- and micronu- trients. The tubers contain significant amounts of iron, calcium and beta- carotene (vitamin A precursor) as reported by Nkansah (2004). According to Nkansah (2004), a 100 g edible portion of raw tuber consisted of water 75.6 g, energy 394 kJ (94 kcal), protein 1.3 g, fat 0.2 g, carbohydrate 21.9 g, fiber 1.1 g, calcium 17 mg, iron 6.0 mg, thiamin 0.05 mg, riboflavin 0.02 mg, niacin 1.0 mg and ascorbic acid 1 mg. Additionally, according to PROTA (2013), 100 g of the raw tubers contain water (76%), carbohydrate (21%), protein (1.4%), fiber (0.7%), fat (0.2%) and ash (1.0%) amongst other important nutrients. The importance of Frafra potatoes as staple crop has been replaced by other starchy tuber crops such as sweet potato (Ipomoea batatas), yam (Dioscorea spp.) and cassava (Manihot esculenta) (Bennett-Lartey & Oteng-Yeboah, 2008; Dittoh, Bayorbor, Yidana, Abapol, & Otoo, 1998). Additional, the downturn of the crop was fuelled by several factors identified by earlier authors including declining soil fertility, diseased planting materials, pest and disease attack, tuber deterioration in storage, high postharvest losses (20–40%), lack of appropriate postharvest preservation methods, lack of improved tuber size and disease resistant planting materials and improved varieties and limited utilization options (Tanzubil, Alem, & Zakaria, 2005;Tetteh&Guo,1997). Presently, efforts to expand the utilization of root and tuber crops had focused on the development of flours from these crops and utilized at various substitution levels as composite flour with wheat flour for the preparing of bakery and other culinary applications. Additionally, the increasing cost of wheat flour on developing economics has reduced their foreign earnings and several percentages of partial substitution with flours from root and tuber crops have been suggested (Rodrick, 2008). Further, root and tuber flours substitution in pastry and culinary applications reduces the challenge of consumers suffering from celiac disease due to allergy to wheat gliadins. Successes have been reported by authors in some studies (Adegunwa, Adelekan, Adebowale, Bakare, & Alamu, 2017; Aina, Falade, Akingbala, & Titus, 2009;Akonor,Tortoe,& Buckman, 2017;Eriksson,Koch,Tortoe,Akonor,&Baidoo,2014; Shittu, Aminu, & Abulude, 2009;Tortoeetal.,2014). However, substitution of wheat flour with Frafra potato flour in pastry products and other culinary applications was limited, although the physicochemical and proximate composition of the Frafra potato has been reported (Kyesmu & Akueshi, 1989;Nkansah,2004). Although these efforts were aimed at achieving food security within countries, therewastheneedalsotopromotelesser JOURNAL OF CULINARY SCIENCE & TECHNOLOGY 3 known crops to further diversify the portfolio of essential crops available. This was buttress by the efforts of several organizations in Ghana to maintain and improve the utilization of the Frafra potatoes (Sugri et al., 2013). Frafra potato has remained a lesser known and underutilized crop, although it has the potential to contribute to local food security and help in fighting vitamin A deficiency, especially in areas where it was cultivated. As a result of its short shelf life, the tubers may be processed into flour and used in pastry and other culinary applications. Therefore, the study was designed to assess the sensory and nutritional properties of bread and koose (a traditional Ghanaian pastry product), made from composite flours of 10 cultivars of Frafra potatoes. This would provide important information on these varieties, which are targeted for integration into food systems.

Materials and methods Materials

Fully matured Frafra potatoes were obtained from CSIR-Savanna Agricultural Research Institute, Manga-Bawku in the Upper East Region of Ghana. The Frafra potatoes were sorted and cleaned of sand and other foreign materials and stored at room temperature (28°C) prior to processing into flour. Physical characteristics of the 10 varieties of Frafra potatoes obtained are presented in Table 1. Hard wheat flour and other bakery ingredients were purchased from a local supermarket in Accra.

Table 1. Physical characteristics of 10 Frafra potato varieties. Frafra potato Status (improved/ variety Species Local name of variety traditional) Shape/Color AC0102 Solenostemon Nutsugah Piesa (Nutsugah’s Improved Oblong/Light brown rotundifolius Frafra potato) UE009 Solenostemon Garu Piesa (Frafra potato from Traditional Elliptical/Brown rotundifolius Garu) UW010 Solenostemon Jirapa Piesa (Frafra potato from Traditional Oblong/Light brown rotundifolius Jirapa) UW001 Solenostemon Wa Piesa (Frafra potato from Traditional Elliptical/Brown rotundifolius Wa) UW022 Solenostemon Naachem-Tiir (hope for the Improved Obovate/Brown rotundifolius youth) UE023 Solenostemon Manga-moya (well done Improved Fairly round/Brown rotundifolius manga station) UE019 Solenostemon Nangode Piesa (Frafra potato Traditional Obovate/Brown rotundifolius from Nangode) UW020 Solenostemon Maa-Lana (I can’t believe how Improved Elliptical/Brown rotundifolius far I have made it) UE021 Solenostemon WAAPP Piesa 1 (WAAPP Frafra Improved Elliptical/Dark rotundifolius potato) brown AC0201 Solenostemon PGRRI Piesa (Frafra potato from Traditional Fairly round/Brown rotundifolius PGRRI) 4 C. TORTOE ET AL.

Methods Frafra potato flour The Frafra potatoes were washed under potable running water and peeled with a stainless steel knife. The peeled tubers were washed and cut into thin slices (5 mm) into a plastic basin containing a solution of 0.5% sodium metabisulphite. The slices were removed after 10 min and adhering water allowed to drain before spreading thinly on drying trays. Drying was done in a thermostat controlled mechanical dryer (Apex, England) at 60°C for 12 h. The dried slices were milled into a flour using a hammer mill (Full circle- pulverator, Jacobson Machine Works, Inc.) to pass through a 250-µm sieve. The Frafra potato flour obtained was packaged airtight in High Density Polypropylene bags for use later.

Composite flour The Frafra potato flour was mixed with hard wheat flour in proportions (w/w) described in Table 2 to produce Frafra potato–wheat flour composite for bread baking. In preparing koose, Frafra potato flour was made into a composite flour with cowpea (Vigna unguiculata) flour. Cowpeas are the most popular starch– protein seed legumes in West Africa. As a major source of vegetable proteins (20–23% crude protein) and starch (50–67%), they offer a wide possibility of utilization than other legumes (Quin, 1997). In addition, cowpeas are excellent source of niacin, thiamine, riboflavin, water-soluble vitamins and essential minerals such as calcium, magnesium, potassium and phosphorus (Phillips & McWatters, 1991).

Flour products Two products (bread and koose) were produced from the Frafra potato flours. The bread formula was based on method described by Tortoe et al. (2014a) using Frafra potato–wheat composite flour, margarine, sugar and a pinch of salt and baking instant yeast. The method by Tortoe et al. (2014a) has been used by other authors (Akonor et al., 2017). All the ingredients were mixed thoroughly at low speed before kneading into a soft dough. The kneaded dough was allowed to rise before panning and proofing at room temperature. The loaves were baked in a moderately hot oven and allowed to

Table 2. Proportional matrix of Frafra potato flour and wheat flour for bread and koose. Pastry product Frafra potato flour (%) Wheat flour (%) Cowpea flour (%) Bread 20 80 – Bread 30 70 – Koose 20 – 80 Koose 30 – 70 Control-bread – 100 – Control-koose – – 100 JOURNAL OF CULINARY SCIENCE & TECHNOLOGY 5

cool at room temperature before used for sensory evaluation. Koose is a traditional Ghanaian pastry product often eaten with porridge in the morn- ings. In preparing koose, the Frafra potato–cowpea composite flour was mixed with water and whipped until light and fluffy. A pinch of salt and spices were added before scooping and deep frying in previously heated vegetable oil. Deep fried koose was drained of excess oil and allowed to cool before sensory evaluation.

Sensory evaluation Thirty untrained panelists, who regularly eat bread or koose and had previous experience in sensory evaluation, were made to assessed the products, based on common attributes such as color, taste, aroma, softness, sponginess and overall acceptability. The panelists (18 females and 12 males) were nonsmokers aged between 21 and 54 years. However, the panelists were selected based on avail- ability and readiness to partake in the evaluation session. A 9-point Hedonic scale (Stone & Sidel, 2004), with 1 representing dislike extremely and 9 representing like extremely was used for the evaluation. The evaluation was con- ducted in a designated sensory facility with individual booths at CSIR-Food Research Institute accredited to ISO 17025. Panelists were instructed to clean their mouths with a piece of unsalted cracker and rinse with water before tasting subsequent samples. The samples were coded following a randomized design matrix generated using XLSTAT version 2014 before serving. Overall acceptability web design of pastry products was done using Microsoft Excel 2010.

Proximate composition Moisture, ash, fat, protein, crude fiber and carbohydrate (estimated by difference) of the Frafra potato flour products were assessed by standard methods of the AOAC International (AOAC, 2000). Energy was calculated based on the Atwater Factor.

Statistical analysis. The data obtained from the studies compared using analysis of variance (SPSS 17.1), assuming a probability level of p < 0.05. Significantly different means were separated by Duncan’s multiple range test.

Results and discussions Sensory evaluation of Frafra potato pastry products

Bread made from 100% wheat flour, which was the control sample, was rated higher for acceptability compared to those made from Frafra potato–wheat flour composites (Table 3). However, similarities in attributes were observed between some of the varieties. Significant differences (p < 0.05) were observed among bread made from some of the varieties of Frafra potatoes. Among the 6 C. TORTOE ET AL.

Table 3. Sensory scores for partial substitution of Frafra potato bread. Variety Level (%) Color Taste Aroma Softness Sponginess Acceptability UE019 20 7.3 ± 0.8bc 7.7 ± 0.7d 7.9 ± 0.7e 7.9 ± 0.7cde 7.8 ± 0.7c 7.7 ± 0.7d UE019 30 7.4 ± 1.1bc 7.7 ± 0.7d 7.7 ± 0.8de 7.7 ± 0.6cde 7.5 ± 0.8bc 7.7 ± 0.6d UE021 20 7.8 ± 0.8cd 7.4 ± 1.1cd 7.5 ± 0.8de 7.8 ± 0.7cde 7.6 ± 1.0bc 7.6 ± 0.9cd UE021 30 7.4 ± 1.1bc 7.4 ± 1.0bcd 7.4 ± 1.0cde 7.5 ± 1.0bcd 7.6 ± 0.9bc 7.4 ± 0.9bcd UW020 20 7.1 ± 1.0ab 7.7 ± 0.7d 7.7 ± 0.8de 7.3 ± 1.0abc 7.5 ± 1.0bc 7.6 ± 0.7cd UW020 30 6.5 ± 1.5a 6.6 ± 1.3a 6.8 ± 1.3ab 7.2 ± 1.3ab 7.0 ± 1.2ab 6.7 ± 1.1a UW022 20 8.2 ± 0.7d 7.6 ± 1.0cd 7.7 ± 1.0de 8.1 ± 0.7e 7.9 ± 0.7c 7.8 ± 0.7d UE023 20 6.7 ± 1.0a 7.0 ± 1.0ab 7.3 ± 1.1bcd 7.5 ± 1.0bcd 7.4 ± 1.0bc 7.6 ± 1.1cd UE023 30 6.5 ± 1.1a 6.9 ± 0.7a 7.1 ± 1.2bc 7.3 ± 1.7abc 7.3 ± 1.3bc 7.4 ± 1.3bcd UW022 30 7.8 ± 1.0cd 6.8 ± 1.5ab 6.7 ± 1.5a 7.1 ± 1.1ab 7.1 ± 1.2ab 6.9 ± 1.1ab UE009 30 7.4 ± 1.3bc 7.0 ± 1.4abc 7.2 ± 1.0bcd 7.3 ± 1.0abc 7.4 ± 0.8bc 7.2 ± 1.1abc UW001 30 7.8 ± 1.4cd 7.0 ± 1.3abc 6.9 ± 1.2abc 6.8 ± 1.4a 6.8 ± 1.2a 7.0 ± 1.4ab Control 7.9 ± 1.1cd 7.8 ± 0.8d 7.6 ± 0.9de 7.9 ± 1.0de 7.7 ± 0.9c 7.9 ± 0.8d Within a column, means with different superscripts are significantly different at p = 0.05.

Frafra potato bread samples, the highest score for color and taste was recorded for sample UW022 and UE019, respectively. Bread with the best aroma was reported for UE019. Generally, an increase in the percentage of the Frafra potato to 30% resulted in a decrease of the overall acceptability of the bread. The scores for crumb softness and crumb sponginess, which are essential attributes of bread showed that UW022 and UE019, were the best varieties for making soft and spongy bread. Bread made from UW022 was the most acceptable to the panelists, and this was followed by UE019, UW020 and UE021 (Table 3). Generally, all the samples received a score within the likeness range, an indication that Frafra potato was a good raw material for making koose (Table 4). Among the Frafra potato koose samples, the highest scores for color, taste and aroma were obtained for UE021, whereas softness, sponginess and sogginess koose were observed in UE019. The scores for color ranged from 5.5 to 8.2 for UE021 and UE009. Koose made from 30% UE021 recorded the highest score, whereas 30% UE009 had the lowest scores for all the attributes assessed. Preferences for koose ranged from 5.8 for 30% UE009 to 7.8 for 30% UE021 (Table 4).

Nutritional analysis of Frafra potato pastry products

Nutritional assessment of bread showed ash and crude fat content were higher in bread containing Frafra potato flour, but these samples had lower protein levels compared to the control samples (Table 5). While sample UW022 was generally carbohydrate dense (72.58 g/100 g), UE023 was richer in ash, fat, protein, crude fiber and energy. Increasing the proportion of Frafra potato flour resulted in an increase in nutritional components and energy. For example, increasing the proportion of UE019 flour from 20% to 30% resulted in a 15% increase in fat and 11% increase in protein content. Table 4. Sensory scores for partial substitution of Frafra potato in koose. Variety Level (%) Color Taste Aroma Softness Sponginess Sogginess Acceptability AC0102 20 7.3 ± 0.9bcd 7.5 ± 1.2bcd 7.4 ± 1.0bcd 7.3 ± 1.1bcdef 7.4 ± 1.3bcde 7.1 ± 1.3bc 7.3 ± 1.1bc AC0102 30 7.2 ± 1.1bcd 7.4 ± 0.7bcd 7.4 ± 1.8bcd 7.2 ± 0.9bcdef 7.3 ± 0.9bcde 6.7 ± 1.6abc 7.2 ± 0.7bc UE009 20 7.2 ± 1.5bcd 7.1 ± 1.4bc 7.0 ± 1.3b 6.7 ± 1.2b 6.7 ± 1.5b 6.4 ± 1.6ab 6.9 ± 1.5b UE009 30 5.5 ± 2.2a 5.8 ± 1.9a 6.1 ± 0.8a 5.8 ± 1.7a 6.2 ± 2.0a 5.9 ± 2.1a 5.8 ± 2.0a UW010 20 7.5 ± 0.8cde 7.4 ± 0.9bcd 7.7 ± 0.8cd 7.2 ± 1.2bcdef 7.2 ± 1.1bcde 7.1 ± 1.2bc 7.3 ± 0.9bc UW010 30 7.3 ± 1.3bcd 7.6 ± 0.8cd 7.6 ± 1.0bcd 7.6 ± 0.9cdef 7.5 ± 0.9bc 6.6 ± 1.5abc 7.3 ± 0.9bc UW001 20 7.6 ± 1.1def 7.3 ± 1.1bcd 7.3 ± 1.1bcd 6.7 ± 1.3b 7.1 ± 1.1bcde 6.8 ± 1.6abc 7.2 ± 1.0bc UW001 30 7.4 ± 1.1cde 7.3 ± 1.5bc 7.3 ± 0.8bcd 7.0 ± 1.1bc 6.9 ± 1.2bcd 6.8 ± 1.6abc 7.3 ± 1.1bc

UW022 20 7.4 ± 0.9cde 7.3 ± 1.2bc 7.3 ± 0.9bcd 6.9 ± 1.1bc 7.1 ± 1.1bcde 6.5 ± 1.4abc 7.1 ± 1.0b TECHNOLOGY & SCIENCE CULINARY OF JOURNAL UW022 30 7.4 ± 1.1cde 7.5 ± 1.0bcd 7.2 ± 0.9bc 7.2 ± 1.1bcdef 7.2 ± 1.6bcde 6.9 ± 0.9bc 7.1 ± 1.1b UE023 20 7.5 ± 1.2cde 7.3 ± 1.2bc 7.5 ± 0.9bcd 7.1 ± 1.0bcd 7.1 ± 1.0bcde 7.0 ± 1.3bc 7.1 ± 1.2b UE023 30 6.9 ± 2.3bcd 6.8 ± 0.9b 7.3 ± 1.2bcd 6.6 ± 1.7b 6.9 ± 1.8bcd 6.9 ± 1.8bc 7.0 ± 1.6b UE019 20 7.5 ± 1.0cde 7.5 ± 1.2bcd 7.5 ± 0.9bcd 7.9 ± 0.8f 7.7 ± 1.1de 7.1 ± 1.3bc 7.2 ± 1.0bc UE019 30 6.7 ± 1.4bc 7.4 ± 1.0bcd 7.1 ± 0.8bc 7.8 ± 0.8ef 7.5 ± 1.0cde 7.4 ± 1.2c 7.0 ± 1.0b UW020 20 6.6 ± 1.5b 7.2 ± 1.0bc 7.1 ± 1.1bc 7.2 ± 1.1bcdef 7.5 ± 1.3bcde 7.1 ± 1.3bc 7.5 ± 0.9bc UW020 30 7.4 ± 1.2bcd 7.4 ± 0.8bcd 7.5 ± 0.9bcd 7.7 ± 0.7def 7.4 ± 0.9bcde 7.0 ± 1.3bc 7.1 ± 1.2b UE021 20 7.5 ± 1.4cde 7.2 ± 0.7bc 7.1 ± 1.0bc 7.1 ± 0.7bcde 7.2 ± 1.0bcde 6.8 ± 1.5abc 7.4 ± 0.9bc UE021 30 8.2 ± 1.3cde 8.0 ± 1.1d 7.8 ± 1.0d 7.5 ± 1.2cdef 7.7 ± 0.9e 7.3 ± 1.0bc 7.8 ± 1.5c AC0201 20 7.4 ± 1.3cde 7.1 ± 1.2bc 7.2 ± 1.0bcd 6.9 ± 1.5bc 7.1 ± 1.4bcde 6.9 ± 1.6bc 7.5 ± 1.2bc AC0201 30 7.0 ± 1.8bcd 7.2 ± 1.3bc 7.1 ± 1.0bc 7.0 ± 1.3bc 7.1 ± 1.6bcde 7.2 ± 1.3bc 7.3 ± 0.9bc Control 100 8.1 ± 0.9ef 7.3 ± 1.4bc 7.4 ± 1.0bcd 7.3 ± 1.2bcdef 7.6 ± 1.1cde 6.8 ± 1.3bc 7.5 ± 1.0bc Within a column, means with different superscripts are significantly different at p = 0.05. 7 8 C. TORTOE ET AL.

Table 5. Proximate composition (DWB) of bread containing Frafra potato flour. Level Ash Protein Crude fiber Carbohydrate Energy Variety (%) (g/100g) Fat (g/100g) (g/100g) (g/100g) (g/100g) (kcal/100g) UE019 20 2.21 ± 0.03c 12.15 ± 0.04a 14.15 ± 0.01b 2.72 ± 0.36a 68.88 ± 0.44c 440.97 ± 1.40b UE019 30 2.24 ± 0.01c 14.01 ± 0.01b 15.67 ± 0.23c 3.64 ± 0.42a 64.45 ± 0.66b 445.12 ± 2.17b UW022 20 2.12 ± 0.02b 12.12 ± 0.04a 8.22 ± 0.21a 4.97 ± 0.13b 72.58 ± 0.10d 431.85 ± 1.12a UE023 20 3.72 ± 0.02d 20.13 ± 0.23c 14.23 ± 0.04b 5.96 ± 0.10c 55.97 ± 0.20a 461.98 ± 1.45c Control 1.56 ± 0.03a 11.79 ± 0.35a 18.57 ± 0.01d 3.17 ± 0.04a 64.91 ± 0.30b 440.08 ± 2.06b Within a column, means with different superscripts are significantly different at p = 0.05.

Table 6. Proximate composition of koose containing Frafra potato flour. Level Ash (g/ Protein (g/ Crude fiber Carbohydrate Energy (kcal/ Variety (%) 100g) Fat (g/100g) 100g) (g/100g) (g/100g) 100g) UE021 20 3.87 ± 0.02c 22.64 ± 0.24a 16.46 ± 0.20b 4.05 ± 0.02b 52.98 ± 0.44b 481.52 ± 1.21a UE023 20 3.65 ± 0.01b 23.82 ± 0.02b 20.75 ± 0.10c 4.50 ± 0.36b 47.30 ± 0.28a 486.49 ± 1.35b UW020 30 3.66 ± 0.04b 22.04 ± 0.17a 16.25 ± 0.12ab 3.11 ± 0.12a 54.96 ± 0.44c 483.10 ± 0.18ab AC0102 20 3.26 ± 0.05a 25.52 ± 0.24c 20.29 ± 0.43c 4.51 ± 0.01b 46.43 ± 0.73a 496.52 ± 0.10d Control 4.24 ± 0.01d 26.57 ± 0.27d 15.50 ± 0.02a 6.08 ± 0.17c 47.64 ± 0.44a 491.57 ± 0.68c Within a column, means with different superscripts are significantly different at p = 0.05.

Generally, koose containing Frafra potato flour was fairly lower in ash and fat content compared to the control samples (Table 6). However, samples containing Frafra potato flour had higher amounts of proteins than the control sample. Interesting, the UE023 at 20% had the highest protein content (20.75 g/100 g) but contained low levels of carbohydrates (47.3 g/100 g). The highest carbohydrate content (54.96 g/100 g) was recorded for UW020 at 30%. Sample AC0102 had the lowest carbohydrate content (46.43 g/100 g) but highest energy (496.52 g/100 g). However, the fat and crude fiber content obtained for koose containing AC0102 flour were lower comparable to the control sample. Nutritional analysis of the Frafra potato tubers from the five selected varieties based on their high sensory scores showed that the crop was essentially rich in carbohydrate source (89–92%) (Table 7). It contained low amounts of protein, ranging between 4% and 6% of its dry weight. The fat content of the crop was less than 1%. The ash content ranged from 4.1% and 4.7%, making it a possible good source of mineral. The UE021 variety had the highest amount of protein (6%) and fat (0.8%), while UW020 variety contained the highest amount of ash (4.7%). ANOVA showed significant differences (p < 0.05) in proximate composition between the five varieties of Frafra potatoes. However, energy content was similar for all the varieties compared. Interestingly, the protein content from these varieties of Frafra potatoes was higher (4.1–6.2 g/100 g) compared to that of cassava (M. esculenta)(1.0–2.0 g/100 g) (Charles, Sriroth, & Huang, 2005) and lower than cocoyam (Xanthosoma sagittifolium)(8.5g/100g)(Akonoretal.,2017). Generally, the proximate composition of the Frafra potato flour obtained in this studies was similar to that reported by Nkansah (2004), where the author reported 394 kJ JOURNAL OF CULINARY SCIENCE & TECHNOLOGY 9

Table 7. Proximate composition of five varieties of Frafra potato tubers. Variety Ash (g/100g) Fat (g/100g) Protein (g/100g) Carbohydrate (g/100g) Energy (kcal/100g) UE023 4.62 ± 0.08bc 0.69 ± 0.07b 5.11 ± 0.32b 89.58 ± 0.18b 384.95 ± 0.01a UE021 4.23 ± 0.17ab 0.77 ± 0.01b 6.19 ± 0.43c 88.82 ± 0.26a 386.96 ± 0.65a UE022 4.11 ± 0.13a 0.30 ± 0.02a 4.89 ± 0.11ab 90.71 ± 0.21c 385.08 ± 0.60a AC0122 4.12 ± 0.03a 0.26 ± 0.01a 4.08 ± 0.12a 91.54 ± 0.15d 384.85 ± 0.11a UW020 4.65 ± 0.10c 0.27 ± 0.15a 5.22 ± 0.23bc 89.68 ± 0.09b 382.01 ± 1.85a Within a column, means with different superscripts are significantly different at p = 0.05.

UE019_20%B 7.9

Control_K 7.8 UE019_30%B 7.7 7.6 7.5 7.4 AC0201_20%K UW020_20%B 7.3 7.2 7.1

UW020_20%K UW022_20%B

UE021_30%K Control_B

UE021_20%K

Figure 1. Overall acceptability web design of pastry products (B = bread; K = koose).

(94 kcal) energy, 1.3 g protein, 0.2 g fat, 21.9 g carbohydrate, 1.1 g fiber from a 100-g edible portion of fresh Frafra potato tuber. Additionally, these proximate limits were similar to that obtained for wild yam (Shanthakumari,Mohan,&DeBritto,2008), cassava (Charles et al., 2005) and cocoyam (Sefa-Dedeh & Sackey, 2004).

Acceptability

The 30 panelist overall acceptability of the 2 pastry products of the 10 Frafra potatoes is presented in Figure 1. Generally, the two pastry products made from the Frafra potatoes were comparable to wheat flour only (control), especially for sample UW022 bread at 20% substitution and UE021 koose at 30% substitution. The overall acceptability level was 7.8 for UW022 bread at 20% compared to 7.9 10 C. TORTOE ET AL. for wheat flour only (control). In the case of koose, the overall acceptability level was 7.8 for UE021 koose at 30%, higher than 7.5 of the cowpea flour only (control). This indicates that in bread preparation, a substitution of 20% with Frafra potato flour was suitable, whereas 30% substitution level was suitable for koose preparation. These results are similar to studies on cocoyam flours reported by Akonor et al. (2017) with overall acceptability of 15% substitution levels for doughnuts and bread and 20–30% substitution levels for cookies.

Conclusion Sensory evaluation of the products indicated that the Frafra potatoes may be successfully used for bread and koose production with acceptable sensory attributes. For bread, Frafra potato variety UW022 was the most preferred followed by variety UE019. Similarly, in koose production, Frafra potato variety UE021 was the most preferred followed by variety UW020. Products made with lower proportions (20%) of Frafra potato flour substitution had the most preferred attributes and overall acceptability for bread, whereas 30% was accepted for koose production, although the highest energy was obtained for bread of variety UE023 and koose of variety AC0102. The sensory and nutritional properties reported for the two pastry products place the Frafra potato flour as an important ingredient for nutrient-rich pastry products and the crop as a potential contributortofoodsecurityandcould address the economical challenge of the increasing cost of wheat flour on developing economics, especially in sub-Sahara countries.

Funding

The authors are grateful for sponsorship from the West Africa Agricultural Productivity Programme (WAAPP2A) – Ghana.

Conflict of interests

All authors declare that there is no competing interest regarding this publication.

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