Hypothesis: biscuits with the addition of ants nest tuber and Belitung taro are significantly different in the sensory properties, nutritional value, and antioxidant activity of a variety of biscuits compared to biscuits without addition.

The main material used in this study was Belitung taro (Xanthosoma sagittifolium) and ant nest tubers (Hydnophytum formicarum) from the distributor in Sorong City in West Papua, Indonesia (Figure 1 and Figure 2).

Another material was tropicana slim sugar, salt, Max Crimer, Blue Bland Cookies in Mega Mall, The West Papua Indonesia.

Chemical material used in this study was (1) nutritional analysis: protein katalis, H₂SO₄, aquades, borat, BCG asam- MR, NaOH, Na2S2O3, HCl 0.02 N, petroleum ether, buffer HCl-(KC1) bisa pH 4.5, asam acetate pH 1, methanol-PA (2): DPPH analysis: 0.5 mM, methanol, dan vitamin C, vitamin E in Chemix Pratama Yogyakarta.

The chemical composition of fresh biscuits (as prepared on the day of baking) was determined according to the methods of the Association of Official Analytical Chemists International (AOAC, 2006): the total protein content by the Kjeldahl procedure with nitrogen to a protein conversion factor of 5.7; fat content by the Soxhlet method and ash content by carbonization. The total carbohydrate content was calculated by subtracting the sum of moisture, protein, fat, and ash percentages from 100%.

The preparation of dough and baking of the biscuits was based on the study of Krystyjan et al. (2015). Dry ingredients were mixed and then combined with others according to the recipe presented in Table 1. The dough was mixed for 10 min to obtain a homogeneous consistency and then placed into the fridge at ±6 °C for 30 min. The dough was then rolled out and 5 mm thick biscuits with a 60 mm diameter were formed and baked at 200 °C for 12 min. (Figure 3). The biscuits with the ant nest bulb powder addition in amounts of 6% and 7.5% concerning the wheat flour were prepared in the same way as the control sample (biscuits without ant nest tuber powder). The results of all the experiments are given as the average of replicates. Each replicate (biscuit) was obtained from separately prepared batches of dough.

Antioxidant activity by DPPH method was based on (Sompong et al., 2011; Briliannita, 2017 and Hetharia et al., 2020) with modification. DPPH 0.1 M was prepared by diluted 0.0039 g DPPH with ethanol 96% until 100 mL. DPPH solution (1 mL) was mixed with 200 μL aliquot and the absorbance was measured at 515 nm after 30 min incubation. The data was served as mg of vitamin C equivalent (VCE) per L with the help of the vitamin C standard curve (0 – 40 mg.L^-1).

For sensory analyses, the laboratory was equipped with special boxes and fulfilled all the basic requirements stated by SNI 01-2346-2006 (Indonesia National Standard, Organoleptic or sensory testing instructions) and sensory analysis was carried out according to (BSN, 2006; Pauline et al., 2017) with modification. The evaluation was performed by an untrained panel of 27 women and 3 men that were between the ages of 18 and 25 from students of the Nutrition Department Of the Polytechnic Of Ministry Of Health Of Sorong. For each sample, and for the same panelist, four repetitions were done. The evaluation was done on a Five-point hedonic scale. The scale and categories were as follows: good = 5, fair = 3 and poor = 1. Evaluated characteristics were color, aroma, taste, texture, and overall acceptance.

This study used Statistical Product dan Service Solution (SPSS) version 15.0 (Stat Soft, USA). Results were expressed by average ± standard deviation. The effect of the results was performed using the Kruskal-Wallis test (α = 0.05). The samples of individual varieties were evaluated to each other. Furthermore, all samples of individual varieties of biscuits were evaluated against common biscuit (C001).

Table 2 shows the content of essential nutrients in biscuits. After analyzing the data obtained it was found that the addition of ant nest tuber powder did not affect the carbohydrates content in biscuits – the amount of which oscillated around 60.55%. There was, however, a small but statistically significant increase in ash and water content and a significant decrease in protein and fat content in those biscuits that had additional ant nest tuber powder at 6% and 7.5%. Such a decrease can come from the fact that the ant nest tuber powder contains three times more protein and four times more ash than the Belitung taro flour that was used for baking.

Significant increase of water content for this study, because one to two water populations are identified for Belitung taro flour and are highly dependent on the temperature and concentration rather than the, showed higher retrogradation tendency. An increase in relaxation times at 75 – 80 °C is observed for flours and starches corresponding well to the amylograph pasting temperatures revealed using the Rapid Visco Analyzer (Boakye et al., 2019). The results of other research show that Xanthosoma sagittifolium powder proportion, mixing time, and water addition, significantly affect water holding capacity, oil holding capacity, texture, and protein solubility of TVP (p <0.05). The effect of XSP addition on water holding capacity increase when added to 20% (Lindriati, Herlina, and Arbiantara, 2018).

Based on the research of physicochemical properties of starches of five cocoyam cultivars where starch granule sizes varied significantly in length and width, while amylose content ranged from 11.55% (NCe002) to 33.77% (NXs001). Also, water absorption capacity (21 – 36%), pH (4.8 – 5.3), gelling point (60.5 – 69.5 °C), foam capacity (4.46 – 18.28%), bulk density (0.14 – 1.15 g.mL^-1) and swelling power (2.31 – 10.09) varied significantly (p <0.05) among the cultivars. Water content on our research increased (Falade and Okafor, 2013). A significant increase of ash content was not caused by an interaction between Belitung taro flour with ant nest tuber powder. Product ash levels experienced an increase with increasing portions of flour (Belitung taro flour and ant nest tuber powder). This could be because of the high ash content in both materials. Another factor allegedly due to immersion with salt in the preliminary treatment Belitung taro flour. Salt contains minerals including sodium, chloride, and iodine that can be calculated in measuring ash content. Such as in the results of others our research showed that the different sections of Xanthosoma sagittifolium cormels were significantly different (p <0.05) in chemical composition. The apical section of all the species had high protein content while the distal section had high levels of ash, fibre, and minerals. Potassium was the most abundant mineral (763 – 1451 μg.100 g^-1) with appreciable amounts noted for zinc (17 – 51.1 μg.100 g^-1), magnesium (46.7 – 85.0 μg.100 g^-1), and phosphorus (41.6 – 63.1 μg.100 g^-1) (Sefa-Dedeh and Kofi Agyir-Sackey, 2004).

The sensory evaluation analysis is shown in Table 3. According to the data, biscuits supplemented with 6% ant nest tuber powder obtained a higher total score (4.10 ±0.82) in the sample C013 and the same as in the sample C001 (total score 3.80 ±0.71). The overall assessment allowed the classification of the product to be acceptable (3.53 ±0.82) in the case of the maximum additive (sample C014). When comparing particular sensory characteristics of four biscuits directly, significant differences (p <0.05) were observed between the sample C001 and the sample C014. On this basis, it can be concluded that the applied fortification of biscuits with ant nest tuber powder was possible and gave the desired results, at a level of 6%. Slight differences were noticed between the sample C001 and the sample C014 with a 0% and 7.5% supplementation of ant nest tuber powder. In particular, such characteristics as taste, color, aroma, and texture deteriorated. One of the main factors, as regards the deterioration of the taste of biscuits, was ant nest tuber powder; when used in significant quantities, the biscuits were leaving a crumb biscuit on the tongue. Besides, the color of the product depends on the chemical composition of ant nest tuber powder, which in turn depends on the plant species and environmental conditions (Agatonovic-Kustrin et al., 2018). Thus, the flavonoid, vitamin E, phenolic, aldehyde/ketone, terpenoids, and tannins as well as the reducing sugars introduced to the product with ant nest tuber powder affected its color. Curiously, the darkening of color caused by the addition of ant nest tuber powder was not observed by the assessors.