The Influence of Initial Breakage on Size Reduction during Habitual Chewing of a Solid Test Food

A breakage index for characterizing in vitro nut fragmentation and predicting human oral fragmentation

Breakage of food influences eating experience and sensory perception. The aims of the study were to identify an appropriate breakage index and to develop an in vitro method for predicting the ease of oral breakage of nuts. Kernels of five types of nuts were fragmented in vitro using a texture analyzer and 12 subjects therefore performed molar bites. In addition, peanuts were differently roasted (over 0, 15, 25, and 35 min) to vary texture within the same nut type. Projected particle areas were determined using imaging. Two Breakage Indices were compared (1) BI-I, the difference, after and before fragmentation, in square root values of ratios between total projected area and volume [Agrawal et al., 1997, Archives of Oral Biology, 42(1), 1-9], and (2) BI-II, the ratio of the total projected area after and before fragmentation. BI-II gives a stronger linear regression than BI-I between in vivo and in vitro index values for different types of nuts; Pearson's r = 0.834 versus 0.499 (12 subjects with all data pooled). Using BI-II, a subject's regression result in fragmentation tests with differently roasted peanuts was as strong as when testing different nut types: Pearson's r = 0.984 versus 0.964. Since the range of the in vitro BI-II values was 5.5 times smaller in the peanut tests, the finding of a similarly strong regression indicates a high sensitivity of BI-II to detect differences in food texture. BI-II is useful for food industry to determine how easily solid foods break down and thereby compare the potential of flavor release between foods during chewing.

Current Perspectives on Food Oral Processing

Food oral processing (FOP) is a fast-emerging research area in the food science discipline. Since its first introduction about a decade ago, a large amount of literature has been published in this area, forming new frontiers and leading to new research opportunities. This review aims to summarize FOP research progress from current perspectives. Food texture, food flavor (aroma and taste), bolus swallowing, and eating behavior are covered in this review. The discussion of each topic is organized into three parts: a short background introduction, reflections on current research findings and achievements, and future directions and implications on food design. Physical, physiological, and psychological principles are the main concerns of discussion for each topic. The last part of the review shares views on the research challenges and outlooks of future FOP research. It is hoped that the review not only helps readers comprehend what has been achieved in the past decade but also, more importantly, identify where the knowledge gaps are and in which direction the FOP research will go.

The effect of bolus size on masticatory parameters at swallowing threshold in children using a hard, solid, artificial test food

The effect of different bolus sizes on food breakdown has been studied in adults, but not in children. The objective of this study was to study median particle size (MPS) and other parameters of masticatory function at swallowing threshold (ST) in 8–10‐year‐old‐children with two different bolus sizes. A randomized crossover trial was undertaken in 89 eight to ten‐year‐old children. The study was performed with informed consent and ethical approval. The artificial test food used was made of a condensation silicone (Optosil Comfort) following a standardized protocol. Two bolus sizes (three or four quarters of a 20‐mm diameter, 5‐mm thick tablet) were randomized to avoid an order effect and tested in different sessions. Variables were: MPS (X₅₀) at ST, number of cycles until ST, sequence and cycle duration as well as cycles/g. Comparisons were performed with paired t and Wilcoxon tests, regressions and correlations were run. Cutoff for statistical significance was .05. Statistically significant differences were found for all variables; X₅₀ (2.5 ± 0.8 vs. 2.8 ± 0.7 mm, p < .001), cycles until ST (38 vs. 40, p = .022), sequence (25 vs. 27 s, p = .003), and cycle duration (650 vs. 683 ms, p = .015) and cycles/g (27 vs. 21 cycles/g, p < .001), three or four quarters, respectively. In conclusion, in children, as in adults, chewing on a bigger bolus size leads to a larger MPS (X₅₀) at ST. When chewing on a larger bolus the number of cycles increases, but not enough to swallow the same particle size since the number of cycles/g is less with a bigger bolus size.