Food Science Research: October/November 2019

Detection of Spicy Compounds Using the Electronic Tongue

The consumption of spicy food products has increased, resulting in an increased demand for these products. The sensory evaluation of foods containing spicy compounds provides challenges due to their trigeminal innervation and associated sensory fatigue. Thus, for the routine evaluation of spices, a need exists for rapid and objective methods of analysis; the electronic tongue (e‐tongue) provides a potential solution. The objective of this study was to evaluate the ability of the e‐tongue to distinguish among spicy compounds at varying concentrations. Due to the diversity of spicy compounds, seven spicy compounds were selected: capsaicin, thymol, piperine, zingerone, p‐cymene, menthol, and eugenol. For each of these compounds, a low concentration (1.427 × 10−5 to 0.85 mg/L), medium concentration (2.854 × 10−5 to 1.49 mg/L), and high concentration (0.0133 to 30.5 mg/L) were analyzed by the e‐tongue. For each compound, the e‐tongue discriminated among the concentrations with discrimination indices between 72% to 84%. Based on the responses of the e‐tongue sensors, the samples formed three clusters. Cluster 1 contained menthol, eugenol, and p‐cymene, cluster 2 contained capsaicin and thymol, and cluster 3 contained piperine and zingerone. Same‐different sensory testing was completed on a representative sample from each cluster. Untrained consumers (n = 80) distinguished among the three clusters, verifying the clusters identified by the e‐tongue. These results demonstrated that the e‐tongue could be applicable in product development and the routine evaluation of spicy products. Journal of Food Science, Volume 84, Issue 9, September 2019, Pages 2619-2627. Read full journal article here.

Natural Antifungal Peptides/Proteins as Model for Novel Food Preservatives

A large range of ingredients for food and food products are subject to fungal contamination, which is a major cause of destruction of crops, exposure of animals and humans to invasive mycotoxins, and food spoilage. The resistance of fungal species to common preservation methods highlights the necessity of new ways to increase the shelf life of raw material for food and food products. Antimicrobial peptides and proteins (AMPs) are essential members of the immune system of most living organisms. Due to their broad range of activity and their stability to commonly used food processes, they represent promising alternatives to traditional preservatives. However, despite the growing number of reports of potential food applications of these AMPs, the number of approved peptides is low. Poor solubility, toxicity, and a time‐consuming extraction are hurdles that limit their application in food products. Thanks to a deep understanding of the key determinants of their activity, the development of optimized synthetic peptides has reduced these drawbacks. This review presents natural and synthetic antifungal peptides/proteins (AFPs), effective against food‐related fungi, with particular emphasis on AFPs from plant sources. The design of novel antifungal peptides via key elements of antifungal activity is also reviewed. Finally, the potential applications of natural and synthetic AFPs as novel antifungal food preservatives are discussed. Comprehensive Reviews in Food Science and Food Safety, Volume 18, Issue 5, September 2019, Pages 1327-1360. Read full journal article here.

Cold Plasma‐Mediated Treatments for Shelf Life Extension of Fresh Produce: A Review of Recent Research Developments

Fresh produce, like fruits and vegetables, are important sources of nutrients and health‐promoting compounds. However, incidences of foodborne outbreaks associated with fresh produce often occur; it is thus important to develop and expand decay‐control technologies that can not only maintain the quality but can also control the biological hazards in postharvest, processing, and storage to extend their shelf life. It is under such a situation that plasma‐mediated treatments have been developed as a novel nonthermal processing tool, offering many advantages and attracting much interest from researchers and the food industry. This review summarizes recent developments of cold plasma technology and associated activated water for shelf life extension of fresh produce. An overview of plasma generation and its physical-chemical properties as well as methods for improving plasma efficiency are first presented. Details of using the technology as a nonthermal agent in inhibiting spoilage and pathogenic microorganisms, inactivating enzymes, and modifying the barrier properties or imparting specific functionalities of packaging materials to extend shelf life of food produce are then reviewed, and the effects of cold plasma‐mediated treatment on microstructure and quality attributes of fresh produce are discussed. Future prospects and research gaps of cold plasma are finally elucidated. The review shows that atmospheric plasma‐mediated treatments in various gas mixtures can significantly inhibit microorganisms, inactive enzyme, and modify packaging materials, leading to shelf life extension of fresh produce. The quality attributes of treated produce are not compromised but improved. Therefore, plasma‐mediated treatment has great potential and values for its application in the food industry. Comprehensive Reviews in Food Science and Food Safety, Volume 18, Issue 5, September 2019, Pages 1312-1326. Read full journal article here.