The COVID-19 pandemic has brought economic problems on a global scale ^[1][2][1,2]. Thus, all over the world, policymakers had to restrict the activities of companies (e.g., closure of restaurants, hotels, and shopping centers), thus shrinking the economy and increasing unemployment. The aim was to avoid the loss of human lives ^[1][3][1,3].

In this context, policymakers further limited the movement of humans for long periods to decrease contact between humans. Humans were only allowed to leave home in particular situations such as needing medical care, physical activities (in the vicinity where they lived), legal obligations, or shopping. Telework was imposed in the activities, except for workers in essential sectors (e.g., food factories, supermarkets, pharmacies) [4]. Thus, shops that sold food remained open all the time. Moreover, policymakers closed their borders, which led to food availability and distribution problems. All these restrictions may have led to possible changes in food shopping habits ^[5][6][5,6] and it is crucial to study them in different contexts.

At the beginning of the COVID-19 pandemic, consumers focused on panic buying as they were afraid of future shortages ^[7][8][7,8]. On the other hand, consumers also wanted to decrease the number of times they went shopping to reduce the risk of catching the virus. Generally, consumers bought more packaged rice, pasta, milk, and vegetables ^[2][9][2,9]. These situations accentuated supermarket stock-outs, leading to price increases in consumer products [10]. The first confinement brought about changes in human consumption habits, altering, in some cases, their diets. The consumption of processed foods (food with change in the fundamental nature of an agricultural product such as heating, freezing, dicing, juicing) and ultra-processed foods (food is mainly made from substances extracted from food, such as added sugars, hydrogenated fats, and starches) increased, and the consumption of vegetables and fruit reduced. The method of purchasing food products during the COVID-19 pandemic also changed. To avoid getting infected with the virus when physically going to the shops, some people started shopping for food online ^[1][8][1,8].

In this framework, e-commerce increased during the COVID-19 pandemic [11]. However, this trend was already present before the COVID-19 pandemic. In the European Union, about six out of ten consumers aged 16–75 were purchasing services and goods online in 2017. However, in 2007, it was only three out of ten [12]. This increase was accentuated with the COVID-19 pandemic because consumers could receive food at their homes, thus avoiding contact, which reduced the possibility of catching the virus. Therefore, it is essential to understand how consumers changed their online food shopping habits during the COVID-19 pandemic and its implications on retail food markets [13].

According to Klarna’s Survey [14] carried out with 1013 Portuguese consumers aged between 18–65 years in February 2022, 47% of consumers surveyed believe that in a year, they will mostly buy online, showing a growing preference for online shopping and 15% of Portuguese consumers shop online at least once a week. The most purchased products are clothing and shoes (51%), electronics (43%), entertainment (30%), and groceries (26%). The main advantages of online shopping identified by Portuguese consumers are that they can shop from home whenever they want, it saves time, the possibility of comparing prices, and obtaining products at lower prices.

Recently, the online food shopping industry has developed increasingly [15]. The boost in online grocery shopping during the pandemic was due to the confinement imposed on consumers by the health authorities that prevented the free movement of people for long months and the fear of contracting COVID-19 on the trip to supermarkets. On the other hand, online shopping platforms are becoming increasingly user-friendly, helping online sales grow [13]. Despite this development, before the COVID-19 pandemic, online food shopping only accounted for about 5% of total sales [13], so there is still much room for businesses to develop this market. Most grocery shoppers prefer to do it in person in physical stores due to the distrust in e-shoppers to choose the best and freshest grocery store and due to the tendency to buy less healthy and more pre-cooked products online. In addition, hedonic reasons and pleasure in the shopping experience when going to physical stores are also driving factors for shopping in person, due to the time delay between making online purchases and delivery and having to pay for the delivery service [16].

The COVID-19 pandemic has increased online shopping and the interest in studying this new trend. There is still dubiousness regarding the determining factors of online shopping behavior during and after the COVID-19 pandemic ^[1][17][1,17]. Therefore, further research is needed to understand how consumption has evolved during the COVID-19 pandemic and the potential role of e-commerce after the COVID-19 pandemic ^{[17][18][19][20]}[17,18,19,20].

2. OnlLine Grocery Shoppingterature Review

Online grocery shopping is a form of online shopping for food and other household items processed through e-commerce websites or mobile apps [21]. The studies on online grocery shopping started in the 1990s with the rise of the high-tech generation [22], who began shopping online for convenience as it simplified their lives. The Technology Acceptance Model (TAM) was one of the first theoretical models adopted to predict acceptance and purchase intention by online grocery consumers [23]. This model assumes that the acceptance of new technology is influenced by perceived usefulness and ease of use, and this approach is valid for online grocery shopping [21]. According to these authors, perceived ease of use of online shopping demonstrates to consumers that it is useful and positively influences the intention to use it again, although this decision may be affected by the consumers’ environment. Shang and Wu [24] extended TAM to the Expectation Confirmation Model (ECM) developed by Oliver [25], emphasizing that consumer perceived value along with perceived ease of use influence technology acceptance for online grocery shopping. Consumer perceived value involves a positive experience related to satisfaction that determines the intention to continue shopping online. The food literature has sought to determine the elements that affect acceptance and intention to continue shopping online, with a positive experience of online grocery shopping positively affecting future purchasing intention ^{[21][24][26][27]}[21,24,26,27]. Hansen [27] presented a model of acceptance and adoption of online grocery shopping, which is influenced by the following characteristics: perceived social norms (influence of family and friends), the perceived complexity of using the technology, perceived compatibility regarding the perception that online grocery shopping relates to one’s personality, perceived relative advantage of online shopping compared to face-to-face shopping, and perceived risk regarding the quality and payment methods of the online shopping process. The model presented by Hansen [27] has been tested in different studies [28] in which the importance of personal values have been emphasized as determinants of perceived compatibility and, as such, influencers of consumer behavior. Thus, the Theory of Planned Behaviour (TPB) constructed by Ajzen and Fishbein [29] shows that personal values influence consumers’ attitudes measured by the previous positive online shopping experience. However, these personal values are often related to consumers’ characteristics. Many studies suggest that personal characteristics are determinants of online grocery shopping, namely gender, age, education, and income [30]. In general, more technological and innovative consumption tends to be adopted by men, younger consumers, and those with higher education and income levels ^[31][32][33][31,32,33]. However, several studies have been inconclusive about the influence of gender on online grocery shopping ^[27][34][35][27,34,35]. According to Naseri and Elliott [36], online grocery shopping is adopted more by women due to their role in the family. There is also evidence that men are more likely to shop online due to their busy professional lives [33]. Regarding age, several studies indicate that online grocery shopping decreases with age, that is, younger consumers are more accustomed to buying groceries online. Younger consumers have greater technological skills, seek differentiated and innovative consumption, and perceive greater benefits from online shopping, such as timesaving, the possibility of buying at any time, and the fact that it allows the comparison of prices and the buying of products with greater promotions ^[31][36][31,36]. Consumers with higher levels of education are more likely to shop online because they are more confident, have lower perceived complexity of technology, and recognize greater relative advantages (timesaving and ease) in online grocery shopping ^{[30][33][35][37]}[30,33,35,37]. Higher-income consumers tend to embrace online shopping because they are typically busier individuals in terms of work, seeing advantages to online shopping such as convenience and saves time ^[27][35][36][27,35,36]. On the other hand, individuals with higher incomes have more flexible budgets, allowing them to buy differentiated and innovative products, often only online [38]. However, in situations such as the COVID-19 pandemic, online grocery shopping intention cannot be solely related to consumers’ perceptions of the benefits, risks, and satisfaction of shopping online, i.e., solely centered on personal values. This way, specific events can impose particular behaviors, the growth of online grocery shopping being an imposition of the pandemic ^[13][28][39][13,28,39]. A healthier, more diverse, and balanced diet is part of risk management strategies during pandemics [40]. Consumer awareness of the importance of health, wellness, and more sustainable food choices positively altered food and beverage consumer behavior during the COVID-19 pandemic ^[5][6][5,6]. Motivation for better diets, with changes in consumer behavior during the pandemic, positively influenced online grocery shopping as consumers needed access to healthier foods and could not travel to supermarkets as frequently [6]. For example, during the pandemic, the demand for vegetables and fruits grew exponentially on online platforms [13]. Expectation–Confirmation Theory has been used in marketing studies to demonstrate that customer satisfaction can lead to post-purchase behavior [41]. This theory is based on a process that demonstrates that before the purchase behavior, the consumer creates a specific expectation about a product or service that can later be generalized and expanded due to their beliefs in relation to the offer of the same [42]. During the consumption of the product or service, general perceptions are developed that evaluate the product or service consumed in the post-purchase period [43]. Then, the consumer evaluates the relationship between the expectation formed before the purchase and the reality perceived through the post-purchase evaluation to confirm their formulated expectations [44]. This way, the expectation created can directly create satisfaction in relation to the consumption of a product or service, and high expectations can increase the satisfaction of its consumer ^[43][45][43,45]. Thus, customer satisfaction can be defined as using online stores to make their purchases ^[46][47][46,47], with satisfaction being an important determinant of willingness to shop online again. In online shopping, consumers are more likely to develop a sense of satisfaction since services such as interaction provided by surveys and ease of use are more easily perceived as useful [47]. Therefore, satisfaction is an antecedent of online purchasing intention ^[48][49][50][48,49,50]. TConsidering the literature review and the hypotheses that were formulated, the following structural model was defined (Figure 1).