- Introduction
Nowadays, Chronic Non-Communicable Diseases (NCDs) constitute one of the main health problems worldwide, causing 81% of deaths in Latin America and the Caribbean (PAHO Pan American Health Organization, 2019); Also, 39% of deaths caused by NCDs occur in people under 70 years of age. One of the main behavioral risk factors for NCDs is dietary patterns and a few decades ago the diet shifted from using natural ingredients to consuming ultra-processed foods that contain excessive amounts of sodium, saturated fats, and sugars (Monteiro et al., 2019) generating an unbalanced nutritional profile, high in calories and free sugars which are directly correlated with the prevalence of overweight and obesity (Khan et al., 2019; Mojto et al., 2019).
Currently, it is observed that food systems offer a low availability of healthy foods and a high availability of ultra-processed foods, representing an obstacle to the fulfillment of the Sustainable Development Goals (SDGs) proposed by the United Nations Organization (FAO, 2019) where it seeks to improve people's nutrition by promoting nutritious foods and increasing access to healthy diets.
In this context, the reformulation of food products toward reducing sodium, fat, and sugar content is an efficient strategy to offer healthier, nutritious, and sustainable foods, improving public health and food security worldwide. To complement this strategy of generating healthier foods, the gradual reduction of sugars has stood out in recent years for its potential to offer healthier reformulated foods with reduced sensory and hedonic impacts. (Deliza et al., 2021; Lima et al., 2018; Velázquez et al., 2020, 2021).
Despite the large body of research generated to reduce sugar content in foods, few systematic reviews and meta-analyses show the reformulation process’s impact on the sensory and hedonic quality of reformulated foods. So, this review aims to present, for the first time, a systematic review and meta-analysis of the impact of sugar reduction on sensory acceptance of foodstuffs.
- Methods
This study has two parts: the first consists of a bibliometric and systematic analysis to contextualize the study and the second is a meta-analysis of selected papers.
2.1 Bibliometric review
2.1.1 Literature search
The scientific papers were collected in May 2023 from the world’s largest database Scopus. A total of 977 papers were retrieved considering the titles, abstracts, and keywords in English with the inductor words: “liking”, “acceptance”, “acceptability”, “hedonic”, “sugar”, “reduction”, “reduced”, “food”, “foodstuffs”, “development”, published up to 2023. Papers not related to sugar reduction, human studies, and product acceptance were manually excluded based on a preliminary reading of titles and abstracts. The final bibliometric list included 207 studies from 1997 to 2023.
2.1.2 Data processing and analysis
The “Bibliometrix” is a package of R software and “VOSviewer” were used for analysis. “Bibliometrix” includes the main bibliometric analysis methods to perform complete scientific mapping analyses (Aria & Cuccurullo, 2017) used to identify the most relevant authors on the topic, author’s countries, articles with the highest number of citations, and word clouds of frequencies. “VOSviewer” is a freely available software for constructing and visualizing graphical representations of bibliometric maps (Van Eck & Waltman, 2010) expressing the co-occurrence matrix as a semantic network to identify patterns and relationships between words.
2.2 Meta-analysis
The five steps considered in this meta-analysis are described in Figure 1, consisting first of identifying the research question, eligibility criteria, study selection, quantitative synthesis, and data synthesis and analysis of results.
Figure 1. Five steps considered for the meta-analysis.
2.2.1 Identifying the research question
The main research question: What are the associations between sugar reduction and the acceptance of foodstuffs?
2.2.2 Databases, search strategy, and inclusion criteria
Of the 207 studies obtained in the bibliometric review, a manual exclusion was performed by reading the full text of the papers. Inclusion criteria were: 1) full text available, 2) sugar reduction and sensory evaluation of products, 3) more than 50 consumers to ensure data consistency, 4) Using a nine-point hedonic scale, and 5) Participants composed of children and adults.
2.2.3 Study selection
The meta-analysis was performed by adults and children. For the meta-analysis in adults, 8 studies with 32 datasets were included, and are shown in Table 1.
For the meta-analysis in children, 4 studies with 25 data were included in Table 2.
2.2.4 Data analysis
The meta-analysis was conducted in R software (version 4.2.3) using the metafor package (Viechtbauer, 2010). The effect of sugar reduction on acceptance was estimated using a fixed-effect model because the studies are homogeneous in terms of design and response variable (hedonic scale).
To assess the degree of variation between effect sizes in the studies considered in the meta-analysis, the heterogeneity of effect sizes was determined based on the Q statistic and I2 statistic (Cheung, 2019).
- Results and discussion
The bibliometric systematic review included 207 papers, and the meta-analysis of products targeting adults and children included 12 articles (Figure 2).
Figure 2. Flowchart used to search and select papers for bibliometric systematic review and meta-analysis, adapted from the PRISMA (Page et al., 2021).