The influence of service quality, product quality, price, and innovation on customer loyalty at satay restaurant with the customer satisfaction as an intervening variable

this study were all individual customers who had visited a satay restaurant in the province of Daerah Istimewa Yogyakarta with a total sample of 211 respondents. The result of the study shows that service quality, product quality, price, and innovation have a positive and significant impact on customer satisfaction at Satay restaurant in Yogyakarta. © 2023 by the authors. Licensee SSBFNET, Istanbul, Turkey. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).


Introduction
In the current business era, world business competition is increasing rapidly. The existence of increasingly rapid competition makes food business actors continue able to maximize the performance of their companies so they can compete in the market. One area in Indonesia whose culinary industry is growing quite rapidly is the city of Yogyakarta, which is known as a student city. The growth in the number of restaurants in Yogyakarta based on data sources from the Tourism Office has reached 1.225 units in 2022. One of the food businesses that is taking part in feeling the tight competition today is the satay restaurant business. According to culinary expert Prof. Dr. Ir. Murdijati Gardjito stated that in Indonesia alone there are approximately 252 varieties of satay. Yogyakarta already has the most variety of satay with a total of twenty-one types of satays and even every year it continues to grow. 116 according to their expectations, loyalty is created. According to Oliver (2014), customer loyalty is a commitment that has been firmly held by its customers to buy or promote a product in the form of goods or services consistently. Customers who are comfortable with the value and service they receive can become loyal.
According to , service quality is a form of consumer assessment of the level of service received and the level of service expected. The second factor that makes consumers feel satisfied is product quality. The second factor  product quality is a product characteristic related to its ability to meet stated or implied customer needs. The third factor is price, according to Monroe quoted by Wijaya (2020) stating that the perception of quality and the perception of the costs incurred to obtain the product. The fourth factor is innovation. According to Goggin (2008), innovation is an idea, practice or object that is considered new by individuals or other user units. Product innovation will certainly create various product designs to increase the benefits or value received by customers, which in turn will improve product quality as expected by customers. These four variables will later decide consumer attitudes about their evaluation of satay restaurants in Yogyakarta.
The study aims to decide the effect of service quality, product quality, price, and innovation on customer satisfaction at satay restaurants in Yogyakarta. The analytical method used in this study is Structural Equation Modeling (SEM) which was conducted with the help of SmartPLS software. This paper continues with a literature review, analysis, findings and discussion. Paper finally concludes with recommendations.

Literature Review Theoretical and Conceptual Background
Customers who make repeat purchases are known as loyal customers. According to Griffin (2013), loyalty is defined as purchases made by continuous decision-making that has lasted for a long time. Kotller & Keller (2013), Customer loyalty is a form of customer commitment to a product of service, which is reflected in repeated purchases, the number of purchases in the present and the future and the different acceptance rates from competing products or services. Indicators of customer loyalty include repeat purchases, using line products, recommending to others and being immune to competitor's offers (Griffin, 2013) . Customers will feel satisfied or dissatisfied influenced by several factors that precede, these factors are service quality, product quality, price, and innovation.

Service Quality
Quality of service according to Tjiptono (2016) is a measure of how well the level of service provided can match customer expectations. The quality of service is decided by the ability of certain companies or institutions to meet the needs according to what is expected or desired based on the needs of customers or visitors. Experts argue that to achieve the desired level, customer expectations must be adjusted to the services provided by service providers (Thomas, 1999). Service providers need to evaluate services at each stage of service delivery to improve marketing strategies.

Product Quality
According to , the quality of products and services is certainly related to customer satisfaction and company profitability. In the context of this restaurant, good dining quality will lead to higher customer satisfaction. According to Ophuis & Trijp (1995), for products, the intrinsic quality cues consist of appearance, color, shape, and structure which cannot be changed without changing the nature of the product. While the statement of Namkung & Jang (2010), states that indicators of food quality include freshness, thinness, delicacy and food presentation.

Price
According to Kotler & Keller (2019), it is explained that price is one of the elements of the marketing mix that generates revenue, the element generates costs. Price can be interpreted as the amount of money changed for a product or service. There are four dimensions of price, namely price affordability, price compatibility with quality, competitiveness, and price compatibility with benefits.

Innovation
According to Chen et al., (2022), innovation is an important means for businesses to survive and be resilient in the face of external disturbances. Some experts say this innovation is a process of using creative thinking and action in achieving success through the exploration of innovative ideas. Meanwhile, according to other researchers Ribeiro Soriano (2020), the gradual improvement of the existing system is a necessary part and stage of need innovation because innovation does not arrive in the industry in a perfect form.

Customer Satisfaction
Customer satisfaction refers to the ability of a product or service to meet or exceed customer expectations. According to Kotler & Amstrong (2017), customer satisfaction is a form of a person's feelings of pleasure or disappointment that comes from a comparison between his impression of the performance or outcome of a product and his expectations. According to Oliver (2010), achievement of customer satisfaction is the ultimate goal of the company because this will be the basis for affirming customer loyalty and developing long-term relationships.

Service Quality and Customer Satisfaction
Based on previous research conducted by Izogo (2016) stated that service quality has a major effect on customer satisfaction. Other researchers also say this to support and suggest that customer feedback about services needs to be collected in real-time. This study, about service quality, put forward the following hypothesis: H1: Service quality affects customer satisfaction in Satay restaurants product.

Product Quality and Customer Satisfaction
Based on previous research by Tsiotsou (2006) product quality has an influence and contributes to customer satisfaction. According to Rafaelle Oborn., et al (2023), previous research has highlighted that ordinary consumers value organic food as a source of trust. Based on the evidence from the experts, supplying higher quality food has become an important strategy to gain a competitive advantage in the restaurant industry. According to Wijaya (2020) stated that product quality also has a positive effect on customer loyalty. This study, about product quality, put forward the following hypothesis: H2: Product quality affects customer satisfaction in Satay restaurants product.

Price and Customer Satisfaction
Research conducted by Kotler & Amstrong (2017) that price is one of the most important elements and has a significant impact on customer loyalty. Based on earlier research object was a restaurant. In this case, it says that in restaurants, customers do not pay attention to the quality of service if the price and taste of the food provided by the restaurant is sufficient to satisfy customers, and they will make repeat purchases to eat at the restaurant. This study, about price, put forward the following hypothesis: H3: Price affects customer satisfaction in Satay restaurants product.

Innovation and Customer Satisfaction
Several studies have considered innovation as a way for restaurants to achieve a competitive advantage in the industry (Shen, 2022). Based on previous research conducted by Antanegoro, R. Y., Sanusi, F., & Surya, (2017), stated that product innovation has a significant effect on customer satisfaction, so this product innovation can have a significant impact on its customers. Therefore, companies need innovative services to meet and exceed customer expectations. This study, about innovation, put forward the following hypothesis: H4: Innovation affects customer satisfaction in Satay restaurants product.

Customer Satisfaction and Customer Loyalty
Research conducted by Khairunnisa A (2020) that customer satisfaction has a positive and significant effect on customer loyalty. Based on previous research conducted by Griffin (2013), loyalty is a buying behavior that can be defined as a non-random purchase expressed from time to time by several decision-making units. In this case, it says that customer satisfaction has a positive and significant effect on customer loyalty, in which the higher the customer satisfaction, the higher the level of customer loyalty. This study, about customer satisfaction, put forward the following hypothesis: H5: Customer satisfaction affects customer loyalty in Satay restaurants product.

Research and Methodology
The sampling technique used in this study was nonprobability sampling, voluntary sampling, and self-selection. This research has collected data from 211 respondents who have visited satay restaurants in the province of Yogyakarta Special Region. The questionnaire was created using the Google format and shared online via Instagram and WhatsApp.
The Likert Scale has a gradation of strongly disagree with a score of 1, disagree with a score of 2, neutral with a score of 3, agree with a score of 4, and strongly agree with a score of 5 which is used as a measurement scale in this study. Hypothesis testing uses Structural Equation Modeling (SEM) analysis with the SmartPLS program. Figure q shows the research model.

Findings and Discussions
Descriptive Analysis Table 1 displays the results of descriptive statistics being the demographic profile of the respondents. Respondents were dominated by women at 65,9%. In terms of age, the age range of 21-25 years was dominated by 75,4 Based on education, 81.5% of the respondents are undergraduate students, 32,2% have employment status as private employees and respondents have a monthly income level of 24,2%.      Figure 2 shows the measurement model (outer model) to measure how well the influence of service quality, product quality, price, and innovation has on customer loyalty at satay restaurants in Yogyakarta with customer satisfaction as the intervening variable.  Table 4 shows the results of testing hypothesis one on the effect of service quality on satisfaction, which shows the original sample coefficient with a positive value of 0.218. The t-statistic value for this relationship is 3.283 > 1.96 and the p-value is 0.001 <0.05. Thus, service quality has a positive and significant effect on customer satisfaction. Hypothesis 1 which states "Service Quality affects Customer Satisfaction with Rumah Makan Sate Products" is proven or accepted.

Reliability and Validity Assessment
Regarding hypothesis 2 about the effect of product quality on satisfaction, the original sample coefficient has a positive value of 0.253. The t-statistic value for this relationship is 2.539 > 1.96 and the p-value is 0.011 <0.05. Thus, product quality has a positive and significant effect on customer satisfaction. Hypothesis 2 which states "Product Quality affects Customer Satisfaction with Rumah Makan Sate Products" is proven or accepted.
Hypothesis 3 concerning the effect of price on satisfaction shows that the original sample coefficient has a positive value of 0.179. The t-statistic value for this relationship is 2.359 > 1.96 and the p-value is 0.019 <0.05. Thus, the price has a positive and significant effect on customer satisfaction. Hypothesis 3 which states "Price has an effect on Customer Satisfaction with Rumah Makan Sate Products" is proven or accepted.
Hypothesis 4 concerning the effect of innovation on satisfaction shows a positive original sample coefficient of 0.312. The t-statistic value for this relationship is 3.982 > 1.96 and the p-value is 0.000 <0.05. Thus, innovation has a positive and significant effect on customer satisfaction. Hypothesis 4 which states "Innovation has an effect on Customer Satisfaction with Rumah Makan Sate Products" is proven or accepted.
Hypothesis 5 concerning the effect of customer satisfaction on customer loyalty shows a positive original sample coefficient of 0.681. The t-statistic value for this relationship is 15.126 > 1.96 and the p-value is 0.000 <0.05. Thus, customer satisfaction has a positive and significant effect on customer loyalty. Hypothesis 5 which states "Customer Satisfaction has an effect on Customer Loyalty for Rumah Makan Sate Products" is proven or accepted.

Conclusion
Of the four independent variables which include service quality, product quality, price, and innovation, it has been shown to have a significant effect on customer loyalty and customer satisfaction as an intervening variable. In the results of descriptive analysis, the variable that has the highest influence on customer satisfaction is service quality. Therefore, this satay restaurant needs to keep the quality of its services such as adequate restaurant equipment, affordable, spacious, and comfortable location, products made to order, etc. Meanwhile, the variable that has the least influence on customer satisfaction is price. Therefore, the satay restaurant needs to pay attention to and improve several price indicators properly such as offering affordable prices, giving discounts on every purchase, and imposing prices on the satay restaurant by the service, as well as the part and teste served.
In the end, the limitations of the research also need to be acknowledged as a direction for further research. This study uses research objects in restaurants that sell chicken and goat satay in Yogyakarta, while Yogyakarta itself has a large variety of satay. Future studies are expected to use and compare various satay restaurants in Yogyakarta. Regarding the limited number of respondents, it is hoped that further research will increase the number of respondents so that the research results can be relevant. Data collection was only conducted using the google form and without being accompanied by researchers. It is hoped that the distribution of the questionnaires will be conducted directly to customers who are visiting several satay restaurants in Yogyakarta.