Korea is entering a super-aged society beyond the aging society due to the rapid increase in the elderly population (Korean Statistical Information Service, 2021). As the aging population increases, attention has focused on the “silver generation (those aged 65 over)” as an important consumer group (Choi et al., 2013). Accordingly, the development of “silver food” or “functional food” is proceeding in various ways (Kim, 2017).

Unlike the previous silver generation, the new silver generation exerts powerful social and economic influence. In addition, people in this generation are characterized by their high levels of self satisfaction through independent and extensive social activities, showing values that are less resistant to learning new things compared to previous generations (Kim, 2008; Lee, 2020). The importance of enjoying hobbies and leisure activities has increased, and well as the interest in health. Therefore, the consideration of choosing nutritional components when selecting healthy foods and meals has steadily increased. The new silver generation has become one of the main consumers of functional foods (Choi et al., 2013).

The consumption of functional foods among the elder generation has also increased. The survey results of a previous study (Lee and Han, 2015) revealed that bread and rice cakes were in demand as snacks for the elderly. In addition, looking at the results of a survey of the elderly during a study by Shin et al. (2016), bread and rice cakes that were not actually cooked were found to be preferred foods. Therefore, bread and rice cakes were considered to be a preferred food for the elderly. This study also revealed that, although bread is a preferred snack among the elderly, they are more likely to consume bread through purchase rather than making it themselves.

Scones originated in England and are a type of bread with a crispy exterior and a soft texture inside. Scones are a type of quick bread that can be prepared in a short amount of time without fermentation and has a soft and light taste. In Korea, the consumption of scones as a meal substitute has recently been reported to be increasing (Choi and Jung, 2019; Lee and Joo, 2021). However, scones are a type of bread that older people in Korea are relatively unfamiliar with. Since the light taste and soft texture are considered suitable for consumption by the elderly, we intend to manufacture scones for the new silver generation.

Pinus koraiensis is a plant belonging to the pine family and is known commonly in Korea as Hongsong or Five-yeopsong. The leaves and clusters produced by the pine tree are known to have antioxidant properties (Kim et al., 2012). P. koraiensis leaf contain components such as terpenoids, (+)-catechin, β-caryophyllene, gallic acid, and vanillic acid (Jeon and Moon, 2017; Kim et al., 2021). Antioxidants decrease the risk of cancer, diabetes, and high blood pressure, and if the intake of antioxidants is insufficient or the concentration is low in the body, the risk of disease is greater (Kim et al., 2002). Therefore, antioxidants are necessary for the elderly to prevent cancer and chronic diseases (Park et al., 2006).

Additionally, to their antioxidant effects, P. koraiensis leaves have antibacterial activity (Kim et al., 2010). Previous studies have produced Jinmal dasik (a traditional Korean dessert snack) (Kim et al., 2021) and Madeleines (a traditional French biscuit) (Baek et al., 2022) using the leaf powder of P. koraiensis.

In this study, P. koraiensis leaf powder (PKLP) was used to manufacture scones for the new silver generation. The quality and characteristics of the scones which had the addition of PKLP at various concentrations (0, 2, 4, 6, and 8%) were analyzed, providing basic data for food development using P. koraiensis leaf.

Experimental materials

The PKLP used in this experiment was provided by DainNatural Co., Ltd. Flour (Gompyo). The sugar (CJ Cheiljedang), baking powder (Choyafood), and salt (Chungjungone) were purchased online, and the milk (Seoulmilk), butter (Arla), and eggs (YJfood) were purchased at a small supermarket in Seongnam.

Manufacture

Scone batter was prepared with 0, 2, 4, 6, and 8% PKLP by applying the manufacturing method of Lee and Joo (2021) (Fig. 1). The mixing ratio for each batter is as shown in Table 1. The flour, pine nut leaf powder, and baking powder were sieved. After sifting, the sugar and butter were added. The eggs, milk, and salt were then mixed into the batter. The dough was then wrapped in plastic wrap and left to rest in the refrigerator for 40 min. Next, the resting dough was rolled out and divided into four sections in a fan shape. Scones were baked for 12 min in an oven (FDO-7103, Daeyung), which had been preheated to 160°C (lower shelf)/200°C (upper shelf), and then left to cool at room temperature. The cooled scones were placed in an airtight container and stored at room temperature until the experiments were conducted.

Table 1 . Composition of scones added with Pinus koraiensis leaf powder.

Ingredients (g)	Samples
	PS0%	PS2%	PS4%	PS6%	PS8%
Flour	120	117.6	115.2	112.8	110.4
P. koraiensis leaf powder	0	2.4	4.8	7.2	9.6
Butter	46.5	46.5	46.5	46.5	46.5
Egg	30	30	30	30	30
Milk	27	27	27	27	27
Sugar	18	18	18	18	18
Baking powder	3	3	3	3	3
Salt	1.5	1.5	1.5	1.5	1.5

PS, added with P. koraiensis leaf powder..

Figure 1. Scones were supplemented with Pinus koraiensis leaf powder at various concentrations (0, 2, 4, 6, and 8%).

Specific gravity and baking loss

The specific gravity and the baking loss of the scones were calculated according to the AACC (1986) method and Kim and Kim’s (1998) method, respectively, using the following formulae:

Specific gravity=weight of scone/weight of water

Baking loss (%)=[(dough weight−scone weight)/dough weight]×100

Moisture content and pH

The moisture content of the scones was measured using the atmospheric pressure heating and drying method (AOAC, 1984). In brief, approximately 3 g of the sample was placed in a weighing dish and dried at 105°C using a dry oven (LO-FS150, LK Lab). The pH was measured using a pH meter (420 Benchtop, Orion Research) after mixing 27 mL of distilled water with approximately 3 g of the sample.

Chromaticity

A colorimeter (CR-400, Minolta) was used to measure the chromaticity of the scones. The Hunter chromaticity measurement method was used. The brightness, redness, and yellowness were measured using a standard white plate. The control (scones without leaf powder) showed the following colorimetric results: brightness=93.00, redness=0.3125, yellowness=0.531.

Texture

For texture analysis, samples of scone were cut into 3 cm³ cubes. The texture, including the adhesiveness, hardness, springiness, gumminess, and chewiness were measured by texture profile analysis using a CTX texture analyzer (CTX, AMETEK Brookfield). The measurement conditions are as shown in Table 2.

Table 2 . Measuring conditions of scone added with Pinus koraiensis leaf powder.

Measuring	Condition
Distance	5 mm
Start position	0 mm
Trigger load	10 g
Test speed	30 mm/s

Antioxidant activity

The polyphenol, flavonoid, and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging ability were evaluated. The polyphenol content was measured by adding 0.4 mL of Folin-Ciocalteu reagent to 0.4 mL of sample (baked scone) (Folin and Denis, 1912), standing at room temperature for 5 min, then adding 0.4 mL of 10% sodium carbonate. After standing at room temperature (20∼24°C) for 30 min, absorbance was measured at 765 nm with a spectrophotometer (UV-1800, Shimadzu).

To measure the flavonoid content, the method of Lee et al. (1997) was applied. After adding 1 mL of diethylene glycol to 0.1 mL of sample, 0.1 mL of 1 N NaOH was added, mixed, and reacted at room temperature for 1 h, then the absorbance was measured at 420 nm.

The ABTS radical scavenging capacity was measured using the method described in a previous study (Verzelloni et al., 2007). After adding 0.9 mL of ABTS solution to 0.1 mL of sample and reacting for 10 min, absorbance was measured at 734 nm.

Statistical analysis

All experiments in this study were conducted in triplicate. IBM SPSS Statistics 22.0 (IBM Corp.) was used for the statistical analysis. One-way ANOVA was performed, the mean±standard error was expressed, and the significance (P<0.05) between samples was confirmed. For items with a significant difference P<0.05, a post hoc test was conducted by Least Squares Distance analysis method.

Specific gravity and baking loss

Table 3 shows the specific gravity and baking loss of the scones. The results showed that the specific gravity of the scones decreased significantly as the addition amount increased (1.16 in the control group, 1.15 in the 2% group, 1.10 in the 4% group, 1.09 in the 6% group, and 1.02 in the 8% group; P<0.001).The baking loss was found to follow a decreasing trend with the addition of leaf powder in a concentration-dependent manner (11.54% in the control group, 10.45% in the 2% added group, 10.18% in the 4% added group, 9.95% in the 6% added group, and 10.01% in the 8% added group; P<0.001).

Table 3 . Specific gravity and baking loss of scone added with Pinus koraiensis leaf powder.

	Samples
	PS0%	PS2%	PS4%	PS6%	PS8%	P-value
Specific gravity	1.16±0.00c	1.15±0.01c	1.10±0.00b	1.09±0.01b	1.02±0.00a	<0.001
Baking loss (%)	11.54±0.03d	10.45±0.00c	10.18±0.02b	9.95±0.06a	10.01±0.02a	<0.001

Values are presented as mean±SE of three times..

The letters (a-d) that mean in row by different superscripts are significantly different by least significant deviation (LSD) at P<0.05..

PS, added with P. koraiensis leaf powder..

Moisture content and pH

Table 4 shows the moisture content and pH of the different scones. The moisture content tended to increase with the addition of higher concentrations of leaf powder but did not show a specific trend with the addition of different concentrations of leaf powder (19.80% in the control group, 19.96% in the 2% added group, 18.57% in the 4% added group, 20.75% in the 6% added group, and 21.88% in the 8% added group; P=0.115).

Table 4 . Moisture content and pH of scone added with Pinus koraiensis leaf powder.

	Samples
	PS0%	PS2%	PS4%	PS6%	PS8%	P-value
Moisture content (%)	19.80±0.29	19.96±0.13	18.57±0.18	20.75±0.25	21.88±1.70	0.115
pH	5.27±0.01a	5.55±0.01c	5.49±0.01b	5.62±0.00d	6.32±0.00e	<0.001

Values are presented as mean±SE of three times..

The letters (a-e) that mean in row by different superscripts are significantly different by least significant deviation (LSD) at P<0.05..

PS, added with P. koraiensis leaf powder..

The pH also tended to increase with the addition of higher concentrations of leaf powder (5.27 in the control group, 5.55 in the 2% added group, 5.49 in the 4% added group, 5.62 in the 6% added group, and 6.32 in the 8% added group; P<0.001).

Chromaticity

The brightness, redness, and yellowness of the scones were measured (Table 5). Brightness was found to significantly decrease with the addition of leaf powder (88.41 in the control group, 76.48 in the 2% added group, 66.26 in the 4% added group, 63.59 in the 6% added group, and 57.55 in the 8% added group; P<0.001). Redness was also found to significantly decrease as the addition amount increased (control group −4.53, 2% addition group −4.83, 4% addition group −3.75, 6% addition group −3.24, 8% addition group −2.72; P<0.001). Yellowness tended to increase with the addition of leaf powder (29.70 in the control group, 34.40 in the 2% added group, 35.73 in the 4% added group, 35.69 in the 6% added group, and 35.26 in the 8% added group; P<0.001).

Table 5 . Chromaticity of scone added with Pinus koraiensis leaf powder.

	Samples
	PS0%	PS2%	PS4%	PS6%	PS8%	P-value
Brightness	88.41±0.22e	76.48±0.58d	66.26±0.10c	63.59±0.19b	57.55±0.34a	<0.001
Redness	—4.53±0.01b	—4.83±0.11a	—3.75±0.01c	—3.24±0.02d	—2.72±0.08e	<0.001
Yellowness	29.70±0.03a	34.40±0.14b	35.73±0.10d	35.69±0.06d	35.26±0.24c	<0.001

Values are presented as mean±SE of three times..

The letters (a-e) that mean in row by different superscripts are significantly different by least significant deviation (LSD) at P<0.05..

PS, added with P. koraiensis leaf powder..

Texture

Table 6 shows the texture analysis of the scones. The adhesiveness showed no particular trend with the addition of leaf powder (0.07 mJ in the control group, 0.05 mJ in the 2% added group, 0.04 mJ in the 4% added group, 0.07 mJ in the 6% added group, and 0.11 mJ in the 8% added group; P=0.651). The hardness was found to decrease significantly as the concentration of PKLP increased, with hardness values of 253.47 g in the control group, 196.33 g in the 2% added group, 190.43 g in the 4% added group, 162.60 g in the 6% added group, and 161.53 g in the 8% added group (P=0.001). The springiness was found to decrease as the addition concentration increased (4.61 mm in the control group, 4.02 mm in the 2% added group, 3.46 mm in the 4% added group, 3.14 mm in the 6% added group, and 3.37 mm in the 8% added group; P=0.352). Gumminess values were evaluated as 76.40 g in the control group, 44.57 g in the 2% added group, 47.20 g in the 4% added group, 39.43 g in the 6% added group, and 38.27 g in the 8% added group, showing a decreasing trend with the addition of higher concentrations of leaf powder. Although it showed a decreasing trend compared to the control group, it did not show a constant trend (P=0.001). The chewiness values were 3.41 mJ in the control group, 1.74 mJ in the 2% added group, 1.61 mJ in the 4% added group, 1.20 mJ in the 6% added group, and 1.25 mJ in the 8% added group (P<0.001).

Table 6 . Texture of scone added with Pinus koraiensis leaf powder.

	Samples
	PS0%	PS2%	PS4%	PS6%	PS8%	P-value
Adhesiveness (mJ)	0.07±0.04	0.05±0.32	0.04±0.02	0.07±0.02	0.11±0.05	0.651
Hardness (g)	253.47±7.17b	196.33±14.82a	190.43±12.53a	162.60±10.70a	161.53±11.86a	0.001
Springiness (mm)	4.61±0.46	4.02±0.42	3.46±0.58	3.14±0.64	3.37±0.55	0.352
Gumminess (g)	76.40±8.50b	44.57±2.84a	47.20±3.48a	39.43±2.87a	38.27±2.46a	0.001
Chewiness (mJ)	3.41±0.27b	1.74±0.11a	1.61±0.33a	1.20±0.27a	1.25±0.18a	<0.001

Values are presented as mean±SE of three times..

The letters (a,b) that mean in row by different superscripts are significantly different by least significant deviation (LSD) at P<0.05..

PS, added with P. koraiensis leaf powder..

Antioxidant activity

Table 7 shows the antioxidant activity of the scones. The polyphenol content was found to increase significantly as the addition amount increased, with values of 1,883.43 mg/mL in the control group, 2,072.20 mg/mL in the 2% added group, 2,139.23 mg/mL in the 4% added group, 2,339.37 mg/mL in the 6% added group, and 2,405.43 mg/mL in the 8% added group (P=0.007). The flavonoid content was also found to increase significantly with the addition of leaf powder (from 52.17 mg/mL in the control group to 72.40 mg/mL in the 2% added group, 83.20 mg/mL in the 4% added group, 100.23 mg/mL in the 6% added group, and 128.17 mg/mL in the 8% added group; P<0.001). The ABTS radical scavenging ability increased from −7.89% in the control group to 25.36% in the 2% added group, 28.43% in the 4% added group, 60.91% in the 6% added group, and 78.79% in the 9% added group (P<0.001).

Table 7 . Polyphenol, flavonoid, and ABTS of scone added with Pinus koraiensis leaf powder.

	Samples
	PS0%	PS2%	PS4%	PS6%	PS8%	P-value
Polyphenol (mg/mL)	1,883.43±21.73a	2,072.20±21.62a	2,139.23±111.38ab	2,339.37±26.11bc	2,405.43±137.97c	0.007
Flavonoid (mg/mL)	52.17±0.22a	72.40±0.38b	83.20±1.02c	100.23±3.02d	128.17±3.78e	<0.001
ABTS (%)	—7.89±3.04a	25.36±0.80b	28.43±4.34b	60.91±1.00c	78.79±1.47d	<0.001

Values are presented as mean±SE of three times..

The letters (a-e) that mean in row by different superscripts are significantly different by least significant deviation (LSD) at P<0.05..

PS, added with P. koraiensis leaf powder; ABTS, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)..

With the rapid increase in the elderly population in Korea, the development of “silver” food and functional foods is underway. Therefore, this study manufactured scones using PKLP, which is known to have various effects.

In a previous study (Jeong, 2020), it was found that cookies with added Annona muricata leaf powder showed a decrease in specific gravity as the addition amount increased. In another previous study, Madeleines with PKLP added showed different results from this study, as there was no significant difference in specific gravity between the added groups. In the study by Jeong (2020), the baking loss rate of the cookies added with A. muricata leaf powder was found to increase as the addition amount increased, showing the opposite result of this study. The baking loss rate of scone with seoritae powder (Moon et al., 2022) decreased as the addition concentration increased, showing the same results as in this study. Previous studies have shown that adding gluten-free powder reduces baking loss as moisture is not evaporated due to lack of pore formation (Shin, 2015). Specific gravity reflects the amount of air in the dough and is related to density. If the specific gravity is low, crumbling occurs, and if the specific gravity is high, baked goods become dense and the texture is affected (Oh and Kang, 2016; Jeong, 2020). According to a study by Lim et al. (2022), adding a sample to the dough reduces moisture and decreases the volume. Therefore, it is believed that the PKLP used in this study influenced the specific gravity and baking loss.

In previous studies, the moisture content of pine needle cookies (Choi, 2009) and Madeleines baked with PKLP (Baek et al., 2022) did not show a significant difference between the added groups. The moisture content of cookies added with moringa leaf powder (Choi, 2018) increased as the addition amount increased, and the moisture content of scones added with extracted peach liquid (Yang and Kim, 2019) decreased as the addition amount increased, showing different results from this study.

The pH of premature mandarin powder scones (Lee and Joo, 2021) and pine needle cookies (Choi, 2009) showed a decrease as the addition amount increased. In previous studies, PKLP was shown to increase the pH (Woo et al., 1998). In the current study, we also found that the pH increased as the concentration of PKLP in the batter increased.

Among previous studies, Jinmal dasik (Kim et al., 2020) and Madeleines (Beak et al., 2022) with pine nut leaf powder added showed similar colorimetric results to those of this study: the brightness decreased and the redness increased as the amount of pine nut leaf powder added increased. In previous studies, the yellowness of Jinmal dasik (Kim et al., 2020) and Madeleines (Beak et al., 2022) with added pine needle powder was found to decrease as the addition amount increased; however, in the current study, the yellowness of the scones did not show a constant trend.

In scones added with extracted peach liquid (Yang and Kim, 2019), the brightness decreased, and the redness and yellowness increased as the addition amount increased, showing the same results as in this study. Cookies added with moringa leaf powder (Choi, 2018) were found to decrease in both brightness and redness as the addition amount increased, while yellowness remained unchanged. It is thought that the value of redness in this study increased due to the green color of PKLP (Choi, 2018).

In Madeleines baked with P. koraiensis powder (Beak et al., 2022), the adhesiveness did not show a significant difference according to the amount added, showing the same results as in this study. Therefore, the addition of PKLP does not affect the adhesiveness.

In another previous study, the hardness of scones added with green tangerine powder (Lee and Joo, 2021) was found to decrease significantly as the addition amount increased, resulting in the same results as in this study. The scones added with extracted peach liquid (Yang and Kim, 2019) were found to increase in hardness as the addition amount increased, showing the opposite result from this study, where the hardness was affected as the amount of addition of the sample increased.

The springiness of scones added with premature mandarin powder (Lee and Joo, 2021), extracted peach liquid (Yang and Kim, 2019), Litsea japonica fruit powder (Lim et al., 2022), and roasted black bean powder (Moon et al., 2022) did not show any significant differences, showing the same results as in this study.

Scones added with premature mandarin powder (Lee and Joo, 2021) showed a decrease in gumminess and chewiness as the added amount increased. Previous studies have shown that chewiness has a high relationship with texture, which is related to masticatory action and shows a tendency similar to hardness (Kim et al., 2020). Therefore, in this study, it is considered that the results of hardness and chewiness were similar according to the amount of PKLP added.

In a study that tested the antioxidant effect of pine nut leaf extract (Kim et al., 2012), antioxidant activity was demonstrated (polyphenols and 2,2-diphenyl-1-picrylhydrazyl). In Jinmal dasik using pine needle powder (Kim et al., 2020), the ABTS content was found to increase significantly as the leaf powder concentration increased.

In a previous study by Jang et al. (2012), the content of total phenols and antioxidant activity in plants exhibiting antioxidant activity showed a positive relationship, and the antioxidant activity increased as the total phenol content increased. In this study, as the concentration of PKLP increased, the contents of polyphenols, flavonoids, and ABTS all increased, indicating antioxidant activity.

Among the components of P. koraiensis leaf, the polyphenol (+)-catechin is known as a natural antioxidant (Choi et al., 2005). Therefore, it is thought that the use of P. koraiensis leaf will be helpful in the development of various functional foods.

This study was prepared by adding P. koraiensis leaf, known to be rich in antioxidants, to scones. As the amount of PKLP increased, the hardness and chewiness of the baked scone decreased. In addition, as the amount of addition increased, the antioxidant activity increased, and was considered excellent in terms of function. However, since sensory evaluation was not conducted in this study, it is believed that additional research for an appropriate addition ratio is needed by conducting sensory evaluation with a focus on elderly consumers in future studies.

This research was supported by Seongnam Senior Industrial Innovation Center “2023 Age-friendly convergence product practical application support project”.

The authors declare no conflict of interest.

Concept and design: JKP. Analysis and interpretation: HJL, JKP. Data collection: SIR. Writing the article: HJL. Critical revision of the article: JKP. Final approval of the article: all authors. Statistical analysis: HJL. Obtained funding: JKP. Overall responsibility: JKP.