领域：学术论文 · 社会科学

2. Theoretical BackgroundIn this section, we review the consumer acceptance literature. We focus on studies that examine willingness to buy, primarily in Germany, Europe and other Western countries, where data are available.2.1. Consumer AcceptanceBefore the determinants of consumer acceptance can be discussed, the concept of acceptance itself needs to be defined. The term “consumer acceptance” enjoys widespread usage across various research fields and has been extensively reviewed within the food science sector [28,29,30] but there remains a lack of consensus regarding its essential components and a general definition. This overarching construct is employed with ambiguity across different disciplines, including profitability and sufficient user adoption in the form of purchase intention, as well as the absence of categorical rejection towards a product or technology, indicative of a general willingness to engage with it [31,32]. In their scoping review, Baker et al. (2022) define consumer acceptance based on various outcome measurements such as general acceptance, willingness to buy, willingness to pay, willingness to try, perceptions, consumption or purchase intention [9]. Wassmann et al. (2021) include the following measures as correlates of willingness to consume in their meta-analysis: willingness to adopt, willingness to eat, willingness to pay, and willingness to try [10]. However, achieving a concise yet comprehensive definition remains a desirable objective, and such a task exceeds the scope of this paper.Nonetheless, it is crucial to define acceptance in each study to allow comparability. The existing literature on alternative protein sources centres around two main indicators, willingness to try [11,25,33,34] and willingness to buy [5,23,35,36,37,38,39,40], both of which are pivotal for gauging overall acceptance. Due to the lack of general guidance for selecting the indicators and given our specific interest in the potential of these three alternative protein sources to make substantial contributions to a change in diet, we have chosen to focus solely on willingness to buy, as it offers a direct insight into whether consumers are willing to make a purchase to include a specific protein source in their diets. Willingness to buy indicates the readiness to purchase food products of alternative protein sources (algae, crickets, jellyfish) in a grocery store, which goes beyond just the willingness to try [39]. In the following sections, we focus on the willingness to buy but also discuss the determinants of willingness to try and further correlates of consumer acceptance where previous studies on willingness to buy are lacking.2.2. NeophobiaFood neophobia is one of the most investigated determinants of consumer acceptance, particularly in the context of food innovations. Food neophobia, defined as the aversion to and dislike of novel foods, is a trait that manifests with varying degrees of intensity among individuals [41]. Food neophobia negatively influenced consumer acceptance of algae-based foods [42] as well as post-tasting satisfaction with algae-based food products [43]. Food neophobia had a negative impact on the adoption intention of Spirulina-enhanced foods (a specific type of microalgae) in a sub-sample of Belgian consumers who know a lot about the latest food trends and like to eat but not in the sub-samples of vegetarian and sporty Belgian consumers [44]. Food neophobia also showed a negative effect on the willingness to try [33] and to eat or consume insects among German consumers [45,46,47]. A similar effect could be found for the willingness to adopt insect-based foods [25] and to buy them [39]. A cross-country comparative study (involving the Czech Republic, Germany, Finland, and Sweden) further revealed a negative effect on the willingness to buy insect-based foods [38], while the meta-analysis indicated a negative effect on the willingness to consume [10]. Furthermore, food neophobia negatively influenced the attitude towards consuming jellyfish [40].When food is processed before sale, which is likely for the protein sources under study, a phobia against novel food technologies may also be relevant for consumer acceptance of such foods. Food technology neophobia is defined as the resistance to new or modern food technologies [48]. The effect on the consumer acceptance of algae-based products is not clear yet. Embling et al. (2022) did not find a significant effect [42]. However, the consumer willingness to consume insects [10,46] and readiness to adopt insects as meat substitutes [25] are influenced negatively by food technology neophobia. The relationship of food technology neophobia and consumer acceptance of jellyfish is still unclear.To summarise, it is reasonable to assume that food neophobia is associated with low consumer acceptance of alternative protein sources. However, the evident lack of understanding of how food technology neophobia impacts consumer acceptance of algae and jellyfish necessitates further investigations.2.3. Familiarity with New FoodsFamiliarity with the concept of consuming algae and insects as well as past consumption experiences are also important determinants of consumer acceptance [5,25,47]. Perceiving algae-based food as tasty, edible and familiar significantly increased acceptance [42]. People who are familiar with eating insects are more likely to adopt insects in their diets [25] and be willing to consume insects [10]. In contrast, Lammers et al. (2019) have found no effect of familiarity on willingness to consume insect burgers [46]. To the best of the authors’ knowledge, no studies have specifically investigated the impact of familiarity on the consumer acceptance of jellyfish-based foods. However, there appears to be a general tendency for familiarity with the sea environment to positively influence the consumption of jellyfish [40].Previous experiences with algae-based food have a positive impact on willingness to try and adopt algae into the diet [11]. Furthermore, experiences with eating insects lead to a higher willingness to try and adopt insect-based foods [11,33], to eat insect-based foods [39,45,46] and to buy insect-based food products [35,38]. However, a meta-analysis showed only a middle composite effect size of experience with willingness to consume insect-based foods (r = 0.35) [10]. Previous experiences with eating jellyfish lead to a higher willingness to try and adopt jellyfish in the diet [11].Based on the previous findings, both familiarity and experience might have a positive effect on consumer acceptance of algae, crickets and jellyfish. However, some clarity is needed considering scholars that have found no or only a small effect, necessitating a unified research approach.2.4. Food-Related HabitsFood-related lifestyle links individuals’ values with their eating behaviours, incorporating aspects such as food involvement and food innovativeness, as outlined in the food-related lifestyle framework by Brunsø et al. (2021) [49]. Food involvement refers to the extent to which individuals engage with and take an interest in different aspects of food [49]. Those with high food involvement regard food as an important part of their lives, dedicate considerable time and resources to it, and view it as essential for achieving personal goals [49,50]. Previous studies indicate that food involvement positively influences the intention to adopt Spirulina-enhanced foods among consumers who enjoy eating, though this effect is not observed among vegetarians, sporty individuals, or those well informed about the latest food trends [44]. Moreover, food involvement does not impact the willingness to try insect-based foods [51]. To the best of the authors’ knowledge, no studies have investigated the relationship between food involvement and the acceptance of jellyfish-based foods.Another aspect of the food-related lifestyle is food innovativeness, which refers to the extent to which individuals adopt and integrate novel culinary practices and ingredients into their dietary habits [49]. In the absence of previous research on the relationship of food innovativeness and the consumer acceptance of alternative protein sources, Mazhar & Zilahy (2023) show that food-related lifestyles (including food involvement and food innovativeness) are moderately correlated to green food purchasing behaviour [52]. Furthermore, sensation seeking, a related construct, has a positive effect on willingness to consume insects in Germany [46]. Moreover, a meta-analysis revealed that food sensation and innovation seeking have a strong composite effect on willingness to consume insects (r = 0.29) [10].A consistent research approach is required to bridge the knowledge gap about the direction and effect of food involvement and food innovativeness on consumer acceptance of algae, crickets and jellyfish.The meat consumption of consumers is an important determinant of consumer acceptance of proteins from alternative sources [5]. A strong belief in the benefits of eating meat is associated with lower acceptance of algae-based foods among meat consumers [42]. Additionally, consumers with a high rate of weekly meat intake are less likely to choose snacks made out of algae (besides lentils/beans snacks, insect snacks, and hybrid meat snacks), with both the number of meat-eating days and preferred portion size serving as significant predictors of their dietary preferences [53]. Those following a vegetarian or vegan diet are less willing to eat insects [47]. Furthermore, consumers who perceive meat as nutritious, healthy, and strongly focusing on its taste are less inclined to adopt insects as meat substitutes [25]. However, consumers intending to reduce their meat consumption show higher readiness to adopt insects as meat substitutes [25]. Contrary to these findings, Lammers et al. (2019) reported that higher meat consumption is linked to higher acceptance of food containing invisible insects, although this effect disappears when other factors influencing the acceptance (e.g., sensation seeking, sustainability consciousness, food disgust) are considered [46]. A meta-analysis found only a small effect size between willingness to consume insects and meat consumption (r = 0.08) [10]. Schäufele et al. (2019) found no effect of meat consumption on the willingness to try insect-based food [33]. The relationship between meat consumption and consumer acceptance of jellyfish is still unclear.In summary, it could be assumed that (high) meat consumption is associated with low consumer acceptance of algae-based protein. However, there is a clear knowledge gap regarding how meat consumption influences consumer acceptance of crickets and jellyfish. A consistent research approach is necessary to better understand its role.

翻译考点：
考点1：【desirable objective】应该译为“理想目标”。
考点2：【existing literature】应译为“现有文献”。