Development of Instant Puree from Native Potatoes (Solanum andigenum) and Black Mashua (Tropaeolum tuberosum) Fortified with Black Quinoa (Chenopodium quinoa) ^†

Abstract

In Peru’s Andean region, a diversity of seeds and tubers with high nutritional value and health benefits are grown. Nevertheless, chronic malnutrition and obesity emphasize the need to take advantage of our agricultural wealth to improve public health and ensure sustainable development. The aim of this study was to develop an instant puree with native potatoes (Solanum andigenum) and black mashua (Tropaeolum tuberosum) fortified with black quinoa (Chenopodium quinoa). This study employed a simplex centroid mixture design. The proximal compositions of the three formulations developed were as follows: moisture content of 9.37 ± 0.13% to 9.45 ± 0.06%, ash content of 3.34 ± 0.02% to 3.79 ± 0.17%, protein content of 9.48 ± 0.25% to 11.16 ± 0.38% and total carbohydrate content of 72.81 ± 0.35% to 74.98 ± 0.22%. The samples showed significantly higher antioxidant (7280 ± 113.5 µg trolox/g powder to 12914 ± 604 µg trolox/g powder) and phenolic (3444 ± 241 µg gallic acid equivalent (GAE) /g powder to 7044 ± 322 µg GAE/g powder) content than the control sample. Also, the results of the techno-functional properties of the samples were as follows: water absorption capacity 3.56 ± 0.92 g H₂O/g to 3.95 ± 0.07 g H₂O/g, solubility 14.45 ± 0.07% to 17.88 ± 0.15% and in vitro protein digestibility 70.27 ± 0.05% to 71.61 ± 0.8%. The samples demonstrated an adequate balance of amino acids compared with the control sample. The sensory characteristics of rehydrated powders were determined. Therefore, in a fast-paced world where convenience food options are part of a continuously expanding market, a nutritionally improved instant puree from ancestral crops is not only more nutritious and tastier but also contributes to sustainability and promotes culinary diversity.

1. Introduction

Peru is the leading potato producer in Latin America, with the more than 4.5 million tons per year produced being the livelihood of more than 700,000 Peruvian families, growing over 4000 varieties of native potatoes (Solanum andigenum). These varieties are grown in different regions of the country, especially in the Andes, where climatic and geographical diversity has encouraged the development of a wide range of potatoes with different colors, shapes, textures and flavors. Purple and red potato varieties are abundant in anthocyanins and flavonoids. Here, this tuber has an excellent culinary quality, and it has long been part of the basic diet of the Andean Peruvian population [1].

Mashua (Tropaeolum tuberosum) is a tuber originally from the Peruvian Andes that grows between 3500 and 4100 m above sea level, and it extends to countries such as Bolivia, Colombia and Ecuador. Among Andean tubers, it boasts one of the highest yields, with productivity reaching up to 70 tons per hectare, and it is one of the simplest to cultivate. For centuries, this tuber has been utilized in traditional medicine for various ethnic groups in the Andean regions of South America and it is considered a valuable source for developing functional foods due to its impressive nutritional and health-promoting properties. It possesses a significant diversity in shapes and colors, varying from yellowish-white to dark reddish-purple. This last variety has eight to ten times higher antioxidant activity than yellow-colored varieties [2].

Quinoa (Chenopodium quinoa) is an Andean seed that is considered an excellent source of macro- and micronutrients. This gluten-free crop possesses an excellent amino acid composition and bioactive compounds, which have been recognized for their significant health benefits, including their roles as antioxidants, hypolipidemic agents, antidiabetic agents, anti-inflammatory agents, and anticancer agents. Darker quinoa seeds contain higher levels of phenolic compounds and have greater antioxidant properties [3].

Over recent years, plant-based convenience foods have become increasingly important in modern diets because of the need to consume easy-to-prepare and time-saving healthy meals. Instant puree products are part of a continuously expanding market of convenience food options. This research centers on the development and characterization of an instant puree from native potatoes (Solanum andigenum) and black mashua (Tropaeolum tuberosum) fortified with black quinoa (Chenopodium quinoa).

2. Materials and Methods

2.1. Raw Material

The Andean potato Azul (Solanum andigenum) and mashua (Tropaeolum tuberosum) were acquired from Condorcocha Huamanga, Ayacucho, and quinoa (Chenopodium quinoa) was purchased from a local market in Lima, Peru. The control sample was a commercial instant puree that was obtained from a local market in Lima, Peru.

2.2. Design of Experiment (DOE)

The design of the experiment was a simplex centroid mixture design using Minitab 19 software (Stat-Ease, Inc., Minneapolis, MN, USA). Two independent variables were used: X1—mashua (10–40%) content and X2—potato (40–70%) content. The protein (%) content, polyphenol (µg GAE/g powder) content and antioxidant activity (µg Trolox/g powder) were determined as the response variables, as shown in

Table 1. Design of experiment (DOE).

Formulations	Std Order	Run Order	PtType	Blocks	Andean Potato	Mashua	Protein (%)	TPC (µg GAE/g Powder)	DPPH (µg Trolox/g Powder)
F1	5	1	−1	1	0.7	0.1	9.48 ± 0.25	3445 ± 241	12,915 ± 604
F2	1	2	1	1	0.4	0.4	11.16 ± 0.38	7044 ± 322	7281 ± 113
F3	2	3	1	1	0.625	0.175	9.91 ± 0.37	4651 ± 223	11,877 ± 659
F4	4	4	−1	1	0.55	0.25	10.25 ± 0.28	5543 ± 253	10,755 ± 259
F5	3	5	0	1	0.475	0.325	10.70 ± 0.35	6231 ± 271	8842 ± 193

F1: formulation 1; F2: formulation 2; F3: formulation 3; F4: formulation 4; F5: formulation 5; TPC: total phenolic content.

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2.3. Sample Preparation

Formulations of dehydrated purees were developed with different amounts of native potato (Solanum andigenum) and mashua (Tropaeolum tuberosum), keeping the quinoa (Chenopodium quinoa) content constant. The tubers (potato and mashua) were washed, cut into thin slices and cooked at 80 °C for 9 min. The quinoa, previously washed, was cooked at 80 °C for 8 min. All three samples were dehydrated by an infrared dryer (IRC D18, Irconfort, Seville, Spain) at 40 °C for 16 h, 24 h and 12 h, respectively. Then, the samples were ground in a food shredder (Grindomix GM200, Restch, Haan, Germany) and sieved (300 µm) to obtain a fine powder to finally be mixed in proportions according to Table 1 and stored in polyethylene bags at room temperature for subsequent analysis.

2.4. Characterization

2.4.1. Proximal Composition

This analysis was performed using official methods. The moisture content was determined at 110 °C to a constant weight, the ash content was determined by the ignition method (550 °C for 72 h), and the fat content was determined with hexane for 9 h. The total protein (% nitrogen × 6.25) was analyzed by a Kjeldahl analyzer (UDK 139, VELP, Usmate Velate, Italy).

2.4.2. Determination of Mineral Content

The mineral content (Ca, Cu, Fe, K, Mg, Na, P, Zn) was determined by atomic absorption spectrophotometry (Nexion 350x, Perkin Elmer, Waltham, MA, USA) [4].

2.4.3. Determination of Amino Acid Profile

The amino acid profile was quantified by HPLC (ARC, Waters, Milford, CT, USA) [5], with a 150 mm × 3.9 mm inner diameter C18 reverse-phase column. All measures were performed in duplicate.

2.4.4. Antioxidant Activity

The antioxidant activity was determined by spectrometry with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method at 517 nm, and with the 2,2′-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) method at 734 nm (UV 1280 Vis Spectrophotometer Shimadzu, Kyoto, Japan) [6]. The results were expressed as µg Trolox/g powder and were performed in triplicate.

2.4.5. Total Phenolic Content (TPC)

The TPC was determined by the Folin–Ciocalteau method [6] at 760 nm (UV 1280 Vis Spectrophotometer Shimadzu, Kyoto, Japan). The results were performed in triplicate and were expressed as the µg of gallic acid equivalent (GAE)/g powder.

2.4.6. In Vitro Protein Digestibility

This was determined by the method of Tapia et al. [6] with slight modification. Analyses were performed in duplicate, and the results are expressed as:

IVPD (Digestibility (%) = 65.66 + 18.10 × (pH 0 min − pH 10 min))

2.4.7. Solubility

The solubility was determined by dissolving 0.5 g of powder in 20 mL of distilled water in a volumetric flask, followed by vortexing for 5 min and centrifuging at 3000 rpm for 5 min. In total, 20 mL of the supernatant was taken and heated to 105 °C for 2 h. Solubility (%) was calculated by weight difference [4].

2.4.8. Water Holding Capacity (WAI)

This was determined by dissolving 1 g of sample in 50 mL of distilled water in a centrifuge tube and leaving to stand for 30 min at room temperature followed by centrifuging (HettichZentrifugen-Mikro, München, Germany) for 15 min at 4000 rpm. The WAI was determined as the weight of the gel obtained after removal of the supernatant per unit weight of original dry solids [4].

2.4.9. Sensory Analysis

A panel of 30 university students between 18 and 26 years old evaluated the appearance, flavor, texture and overall acceptability. The test was based on a 9-point hedonic scale (1 = dislike extremely and 9 = like extremely).

2.5. Statistical Analysis

Analysis of variance (ANOVA) was analyzed at a 95% significance level with Minitab 19.0 Software (Minitab Inc., State College, Palo Alto, CA, USA).

3. Results and Discussion

According to Table 1, F2 presented the highest protein content (11.16 ± 0.38%) and the highest amount of TPC (7044 ± 322 µg GAE/g powder), while F1 presented the highest antioxidant activity by DPPH (12,915 ± 604 µg Trolox/g dm), followed by F3 with 11,877 ± 659 µg Trolox/g dm, which also presented a high protein content (9.91 ± 0.37%). For these reasons, F1, F2 and F3 were chosen for the subsequent analysis.

The proximate composition is presented in

Table 2. Proximal composition of instant purees from native potatoes (Solanum andigenum) and black mashua (Tropaeolum tuberosum) fortified with black quinoa (Chenopodium quinoa).

Sample	Moisture (%)	Ash (%)	Protein (%)	Fat (%)	Carbohydrates (%)
CS	9.40 ± 0.12 A	3.76 ± 0.36 A	8.1 ± 0.4 C	0.95 ± 0.06 D	77.9 ± 0.3 A
F1	9.45 ± 0.06 A	3.34 ± 0.02 B	9.48 ± 0.25 BC	2.75 ± 0.01 C	75.0 ± 0.2 B
F2	9.33 ± 0.07 A	3.76 ± 0.04 B	11.16 ± 0.38 A	2.94 ± 0.04 A	72.8 ± 0.3 D
F3	9.37 ± 0.13 A	3.79 ± 0.17 A	9.91 ± 0.37 B	2.84 ± 0.02 B	74.1 ± 0.3 C

Results are expressed as means ± SD (n = 3). A, B, C and D values in the same column with different letters differ significantly when p < 0.05.

. All three formulations showed higher protein content than the control sample, as well as in comparison with the other commercial brands in Peru and abroad (7.14% to 8.4% protein content). Formulation 2 presented higher protein (11.06 ± 0.38%) content than the dehydrated puree (9.92%) from native potato (Solanum andigenum) and oca (Oxalis tuberosa) fortified with quinoa (Chenopodium quinoa), which had 40%, 30% and 30% content, respectively, as reported by Inca [7]. Also, this last puree presented less fat content than the formulations (2.46%). The control sample showed more carbohydrate (77.89 ± 0.33%) content and less fat (0.95 ± 0.06%) content than the formulations. The moisture content had 9.5% accordance with the Peruvian regulation NTP 011.808.

The results of TPC, DPPH, in vitro protein digestibility, solubility and water holding capacity are shown in

Table 3. TPC, DPPH, in vitro digestibility, solubility and water holding capacity of instant purees made from native potatoes (Solanum andigenum) and black mashua (Tropaeolum tuberosum) fortified with black quinoa (Chenopodium quinoa).

Sample	TPC (µg GAE/g Powder)	DPPH (µg Trolox/g Powder)	In Vitro Protein Digestibility (%)	Solubility (%)	Water Holding Capacity (g/g)
CS	1071 ± 113.5 D	5654 ± 188,3 C	68.21 ± 0.74 B	7.64 ± 0.13 D	7.5 ± 0.16 A
F1	3445 ± 241.5 C	12,915 ± 604 A	71.61 ± 0.8 A	14.45 ± 0.34 C	3.56 ± 0.09 C
F2	7044 ± 322.6 A	7281 ± 113.5 B	70.27 ± 0.38 A	17.88 ± 0.15 A	3.95 ± 0.07 B
F3	4651 ± 223.4 B	11,877 ± 659 D	70.93 ± 0.75 A	16.21 ± 0.22 B	3.73 ± 0.06 C

TPC: total phenolic content, DPPH: 2,2-diphenyl-1-picrylhydrazyl. Results are expressed as means ± SD (n = 3). A, B, C and D values in the same column with different letters differ significantly when p < 0.05.

. All formulations presented a higher amount of TPC (3445 ± 241 µg GAE/g powder to 7044 ± 322 µg GAE/g powder) than the control sample (1071 ± 113 µg GAE/g powder), increasing according to the amount of mashua (17,387 ± 356 µg GAE/g powder) in the sample. The antioxidant activity according to DPPH (7281 ± 113 µg Trolox/g powder to 12,915 ± 604 µg Trolox/g powder) was higher than the control sample (5654 ± 188 µg Trolox/g powder), increasing according to the amount of native potato (15,469 ± 307.7 µg Trolox/g powder) in the sample. All three formulations showed higher in vitro protein digestibility (70.27 ± 0.38% to 71.61 ± 0.8%) and solubility (14.45 ± 0.34% to 17.88 ± 0.15%) than the control sample (7.64 ± 0.13%) However, all three formulations presented a lower water holding capacity (3.56 ± 0.09 g/g to 3.95 ± 0.07 g/g) than the control sample (7.5 ± 0.16 g/g).

The composition of the amino acid profiles is summarized in

Table 4. Profiles of essential amino acids in instant purees made from native potatoes (Solanumandigenum) and black mashua (Tropaeolum tuberosum) fortified with black quinoa (Chenopodium quinoa).

Amino Acids	CS	F1	F2	F3	FAO%
	(mg Amino Acid/g Protein)
Aspartic acid	124.1 ± 1.17 B	139.9 ± 0.5 A	104.4 ± 1.7 D	117.7 ± 1.9 C
Glutamic acid	84.3 ± 1.67 D	171.5 ± 1.8 A	124.9 ± 1.4 C	145 ± 28 ± 1.6 B
Serine	21.1 ± 1.83 C	45.78 ± 0.1 A	38.2 ± 1.4 B	43.1 ± 1.6 A
Histidine	1.58 ± 0.44 C	20.4 ± 1.3 A	16.1 ± 1.4 B	18.2 ± 1.6 AB	15
Glycine	22.8 ± 1.8 D	47.5 ± 1.0 A	32.3 ± 1.7 C	36.4 ± 1.9 B
Threonine	21.5 ± 1.6 D	46.6 ± 1.0 A	34.3 ± 1.6 C	38.6 ± 1.8 B	23
Arginine	46.2 ± 0.9 A	21.1 ± 1.6 B	19.8 ± 0.4 B	21.8 ± 0.2 B
Alanine	19.1 ± 1.9 D	59.1 ± 0.9 A	36.8 ± 1.6 C	41.5 ± 1.8 B
Proline	25.3 ± 1.5 D	64.2 ± 1.8 A	48.4 ± 1.2 C	54.6 ± 1.4 B
Tyrosine	18.2 ± 1.1 D	37.1 ± 1.2 A	25.8 ± 0.5 C	29.1 ± 0.6 B	38
Ammonia	32.6 ± 1.2 C	43.2 ± 1.7 A	29.0 ± 1.4 C	32.7 ± 1.6 C
Valine	26.7 ± 1.5 D	55.92 ± 1.0 A	42.5 ± 0.3 C	48.0 ± 0.32 B	39
Methionine	6.34 ± 0.2 C	11.9 ± 1.1 B	14.1 ± 1.1 A	13.1 ± 0.3 AB	22
Cysteine	1.9 ± 0.2 C	3.8 ± 0.09 A	2.96 ± 0.3 B	3.4 ± 0.4 AB
Isoleucine	17.9 ± 1.4 D	38.7 ± 1.01 A	27.94 ± 1.0 C	31.5 ± 1.1 B	30
Leucine	49.7 ± 1.6 D	91.9 ± 0.6 A	70.30 ± 1.7 C	79.3 ± 1.9 B	59
Phenylalanine	25.5 ± 1.8 D	44.35 ± 0.9 A	30.32 ± 1.40 C	35.9 ± 1.6 B
Lysine	27.94 ± 1.64 D	56.08 ± 1.5 A	36.75 ± 1.63 C	44.8 ± 1.8 B	45
Tryptophan	5.93 ± 0.57 D	14.88 ± 0.23 C	21.39 ± 0.84 A	19.3 ± 0.1 B	6

Results are expressed as means ± SD (n = 3). A, B, C and D values in the same column with different letters differ significantly when p < 0.05.

. Compared to the control sample, the predominant amino acids were threonine (34.3 ± 1.6 to 46.6 ± 1.0), valine (42.5 ± 0.3 to 55.9 ± 1.0) and phenylalanine (30.3 ± 1.4 to 44.4 ± 0.9). The three formulations showed a balanced profile of essential amino acids according to the FAO/WHO recommendations. These formulations showed higher contents of specific amino acids: leucine (70.3 ± 1.7 to 91.9 ± 0.6), lysine (36.8 ± 1.6 to 56.1 ± 1.5) and tryptophan (14.9 ± 0.2 to 21.39 ± 0.84). Quinoa (Chenopodium quinoa) provided amino acids, especially leucine and lysine, to the purees. This last amino acid supports human growth and boosts immune function, making it a crucial nutrient for children [3]. The puree formulations contained high concentrations of tryptophan, more than double and triple the recommended amount according to the FAO/WHO.

Total minerals are presented in

Table 5. Total minerals of instant purees made from native potatoes (Solanum andigenum) and black mashua (Tropaeolum tuberosum) fortified with black quinoa (Chenopodium quinoa).

Minerals (mg/kg)	CS (mg/kg)	F2 (mg/kg)
Calcium	282 ± 22 b	1271 ± 101 a
Copper	1.62 ± 0.08 b	3.12 ± 0.20 a
Iron	9.89 ± 0.62 b	35.4 ± 2.8 a
Potassium	11,489 ± 896 a	11,092 ± 887 b
Magnesium	678 ± 51 b	1462 ± 116 a
Sodium	361.0 ± 28.8 a	168.2 ± 13.4 b
Phosphorus	1517 ± 121 b	3354 ± 260 a
Zinc	6.95 ± 0.55 b	21.0 ± 1.6 a

Results are expressed as means ± SD (n = 3). a, b, c and d values in the same column with different letters differ significantly when p < 0.05.

. Formulation 2 presented a higher quantity of minerals than the control: calcium (1271 ± 101.2 mg/kg), iron (35.41 ± 2.83 mg/kg), potassium (11,092 ± 887 mg/kg), magnesium (1462 ± 116.9 mg/kg), phosphorus (3353.82 ± 260.3 mg/kg) and zinc (21.02 ± 1.68 mg/kg). According to the daily requirements for children between 1 and 3 years old given by the National Institute of Health [8], instant puree (F2) would cover about 15.17% of the daily requirement of iron. Therefore, the puree developed could contribute to reductions in malnutrition and childhood anemia in our country.

In the sensory evaluation, on a scale of 1 to 9, the characteristics of appearance, color, smell, texture and taste had average values of 7.3, 7.0, 8.0, 6.0 and 6.0, respectively. These results show that the puree was liked by the panelists.

4. Conclusions

The use of native Andean tubers instead of commercial tubers such as white and yellow potatoes showed significantly higher antioxidant activity and total phenolic content. Formulation 2 presented the highest amount of TPC 7044.2 ± 322 (µg GAE/g powder), being seven times higher than that of the control sample and presented the highest protein (11.2 ± 0.3%) content. Formulation 1 presented the highest antioxidant activity according to DPPH (12,915 ± 604 µg Trolox/g powder). The addition of quinoa not only increased the protein content but also provided a balanced profile of essential amino acids. The puree was accepted by the individuals, and in comparison to commercial instant purees, the formulations were more nutritious. Therefore, in a continuously expanding market of convenience food options, the instant puree developed is an alternative for the modern diet.