Recipient Organization
RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY
3 RUTGERS PLZA
NEW BRUNSWICK,NJ 08901-8559
Performing Department
Food Science
Non Technical Summary
Raw cranberries are highly unpalatable and are typically processed with sugar and consumed as cranberry juice cocktail (cranberry juice diluted with water and sweetened), jellied-sauce, or whole, dried fruits (e.g., Craisins). Cranberries are often blended with other sweetened fruit juices (e.g., apple, grape) to reduce its astringency and enhance its appeal. The need to add high amounts of sugar (or non-nutritive sweeteners which are often disliked) to cranberries poses a challenge to the industry in light of current dietary recommendations for consumers to limit sugar-sweetened beverages and daily sugar intake. The high economic importance of cranberries to New Jersey agriculture coupled with the well-established role of cranberry polyphenols in human health justifies additional study of the mechanisms underlying consumer acceptance and health impacts of cranberry products.This project has several goals. First, there are large individual differences in astringency perception that influence consumer acceptance or rejection of cranberry products, but they are poorly understood. Our previous studies showed that differences in astringency perception may be related to variation in a common taste gene that controls the ability to taste the bitterness of PROP (6-n-propylthiouracil). By screening individuals for their taste sensitivity to PROP, we can classify people as PROP non-tasters, medium tasters or super-tasters. Specifically, we showed that PROP non-taster status was associated with lower perception of astrigency and greater liking of cranberry juice cocktail (that we modified in astringency) whereas PROP super-taster status was associated with higher astringency perception and greater dislike of cranberry juice cocktail. The first aim of this project is to replicate these findings using cranberry juice cocktail supplemented with cranberry polyphenol extract (CPE). Cranberries are unique among berry fruits in that they have the highest levels of a specific family of polyphenols (proanthocyanidins; PAC) that have been linked to health benefits. Thus, knowing how different consumers react to PAC-supplemented foods would help guide the industry to develop more nutritious products that appeal to different groups of consumers.Astringency is defined as a drying, roughing or puckering sensation on the tongue that persists over time. When astringent polyphenols enter the mouth, they stimulate the release of salivary proteins. These salivary proteins form chemical bonds with the polyphenols which can alter the perception of astringency. We have previously shown that PROP non-tasters and super-tasters secrete different profiles of salivary proteins in response to cranberry juice which could explain why these two groups also respond differently to astringency. Aim 2 of this project is to confirm and extend our previous findings by examining the salivary protein response to cranberry juice supplemented with PAC. We will measure different classes of salivary proteins after oral stimulation with PAC in non-tasters and super-tasters. Since the time course of astringency perception (including recovery from astringency) is poorly understood, we will measure salivary protein responses over time. This experiment will provide important insights into individual differences in astringency perception and will highlight the specific proteins that play a role in astringency perception and recovery.In addition to their involvement in astringency perception, cranberry polyphenols are known to play a role in oral health. Specifically, PAC stimulates the release of specific salivary proteins that have antimicrobial activity against microbes involved in tooth decay and gum disease. An unanticipated finding from our previous study on cranberry juice stimulation of salivary proteins was that PROP non-tasters had lower levels of these specific proteins in their saliva than did super-tasters. This observation is consistent with other studies from the literature showing that PROP non-tasters have more dental caries than super-tasters. Thus, differences in salivary protein responses to cranberry polyphenols may partially explain why non-tasters are at greater risk of oral disease than super-tasters.The third aim of this project is to conduct a 14-day proof-of-concept study where we will administer a daily PAC oral rinse to participants to determine if this treatment will alter salivary protein profiles and the oral microbiome. Specifically, we expect that at the beginning of the trial, PROP non-tasters will have a higher risk profile for oral disease (lower salivary protein responses and a microbial profile that favors a greater abundance of pathogenic microbes) as compared to super-tasters who will have lower risk profile for oral disease (higher salivary protein responses and a microbial profile that favors an abundance of protective microbes). We also expect that by the end of the trial, daily PAC rinsing will raise the levels of anti-microbial proteins and protective microbes more in the saliva of non-tasters as compared to super-tasters. The data generated in this pilot study could pave the way for more sophisticated studies focused on the development of an oral rinse or functional food that could lower pathogenic bacteria natually, without the use of commercial antimicrobial ingredients (alcohol or chlorhexidine).In summary, this work will improve our understanding of individual differences in the perception of astringency and provide important insights into the physiological mechanisms involved in these responses.This work will also assist the industry in improving current products and developing new uses for cranberry-based foods and nutritional products. These innovations are expected to improve the health, nutrition and quality of life for citizens of New Jersey and the nation.
Animal Health Component
20%
Research Effort Categories
Basic
70%
Applied
20%
Developmental
10%
Goals / Objectives
This project seeks to investigate the role of genetic taste variation and salivary protein profiles in the development of astringency, the acceptability of cranberry juice and extracts by consumers, and the potential effectiveness of cranberry polyphenols in maintaining oral health. The specific aims of this project are to:Aim 1: Determine if genetic variation in the ability to taste the bitter compound PROP, a marker for taste perception and food preferences, plays a role in astringency perception and liking for cranberry juice, cranberry juice cocktail and cranberry polyphenol extract (CPE). We will test the hypothesis that PROP non-tasters will perceive less astringency from these stimuli than super-tasters and they will give it higher liking ratings to these stimuli as well.Aim 2: a) Document the profile and time-course of salivary protein release following oral stimulation with cranberry polyphenol extract across PROP taster groups, and b) link these changes to the development of and recovery from astringency. We will test the hypothesis that PROP super-tasters will have elevated levels of selected salivary proteins after oral stimulation and will exhibit recovery from astringency earlier than non-tasters. These data will provide a mechanistic explanation linking individual differences in astringency perception to variation in salivary protein release.Aim 3 (Exploratory): a) Determine if the oral microbiome of PROP super-tasters varies from that of non-tasters; determine if this variation can be linked to differences in salivary protein profiles between the taster groups; and c) determine if a daily cranberry polyphenol rinse will raise the levels of beneficial bacteria, especially in non-tasters who are at greater risk of oral disease. We hypothesize that PROP super-tasters will have greater abundance of beneficial bacteria and salivary proteins that are implicated in host defense responses than non-tasters. We also hypothesize that daily use of a cranberry polyphenol rinse will favor the proliferation of beneficial oral bacteria in both groups, but this effect will be more pronounced in non-tasters who are at greater risk for oral disease
Project Methods
Aim 1: Determine if genetic variation in the ability to taste the bitter compound PROP, a marker for taste perception and food preferences, plays a role in astringency perception and liking for cranberry juice, cranberry juice cocktail and cranberry polyphenol extract (CPE). We will test the hypothesis that PROP non-tasters will perceive less astringency from these stimuli than super-tasters and they will give it higher liking ratings to these stimuli as well.Subject recruitment and PROP taster status:Healthy adults, 18-45 years of age will be recruited from the Rutgers community. They will be screened for PROP taste sensitivity prior to their admittance into the study. Only non-tasters and super-tasters will be studied, medium tasters will be prohibited from participating. The paper disk method, previously tested for validity and reliability, will be used to screen and classify subjects (Zhao et al., 2003).Three types of samples will be tested: 1) Cranberry polyphenol extract solution, 750 uM (CPE); 2) Unsweetened cranberry juice (CJ); and 3) Cranberry juice cocktail (CJC) with 0, 300, 300, 500 and 750 uM added CPE. Cranberry juice will be made from fresh cranberries. Cranberry juice cocktail (cranberry juice + sugar) will be made according to a standard recipe. CPE solution and CJ are used as outside controls.Procedures: Subjects will participate in three 45-min test sessions on separate days. Intensity ratings for key sensory attributes of the samples will be collected using standard, 15-cm line scales anchored with the phrases "very weak" to "very strong." Attributes of interest include: sweetness, bitterness, sourness, astringency, thickness, cranberry flavor and overall flavor. Overall liking of the samples will be collected with a similar scale anchored with "dislike extremely" to "like extremely."Expected outcomes: Non-tasters will perceive less astringency from CPE-supplemented CJC than super-tasters, and will like these samples more than super-tasters. We expect this experiment to replicate our previous findings with tannic-acid supplemented CJC (Melis et al., 2017).Aim 2: a) Document the profile and time-course of salivary protein release following oral stimulation with cranberry polyphenol extract across PROP taster groups, and b) link these changes to the development of and recovery from astringency. We will test the hypothesis that PROP super-tasters will have elevated levels of selected salivary proteins after oral stimulation with cranberry juice (CJ) or CPE, and will exhibit recovery from astringency earlier than non-tasters. These data will provide a mechanistic explanation linking individual differences in the development of astringency to variation in salivary protein release.Subjects: Thirty non-tasters and 30 super-tasters will be recruited using the same criteria as under Aim 1.Procedures:Two types of test samples will be used: 1) CJ; and 2) CPE. Saliva collections include the following: First, resting saliva is collected for 1 min and then the subject rests for 5 min. The subject swishes and swallows the CPE solution, waits 5 min and expectorates all the saliva into a cup. The subject then waits 5 additional minutes and expectorates into a soufflé cup. After a 20-min rest period, the subject repeats the process with CJ.Salivary Protein Analysis:Resting whole saliva will be collected as it flows into the anterior floor of the mouth for 1 minute. The pooled saliva will then be transferred into micro centrifuge tubes in an ice bath and processed for protein analyses according to standard methods. Proteins will be quantified and identified using HPLC-ESI-IT-MS.Expected outcomes: We expect that salivary protein profiles will be different in PROP super-tasters and non-tasters. Specifically, we expect to see higher levels of aPRPs and Cystatins in PROP super-tasters in line with what we have previously observed. We will also probe for differences in gPRPs, mucins, and alpha-amylase between groups, anticipating that super-tasters will have higher levels of these proteins than non-tasters. We also expect that protein levels in the saliva of super-tasters will return to resting levels more rapidly in comparison to non-tasters.Aim 3: a) Determine if the oral microbiome of PROP super-tasters varies from that of non-tasters; b) determine if this variation can be linked to differences in salivary protein profiles between the taster groups; and c) determine if a daily cranberry polyphenol rinse will raise the levels of beneficial bacteria, especially in non-tasters who are at greater risk of oral disease. We hypothesize that PROP super-tasters will have greater abundance of beneficial bacteria and salivary proteins that are implicated in host defense responses than non-tasters. We also hypothesize that daily use of a cranberry polyphenol rinse will favor the proliferation of beneficial oral bacteria in both groups, but this effect will be more pronounced in non-tasters who are at greater risk for oral diseaseQuestionnaires and Assessments: Potential subjects must have visited the dentist for a checkup and cleaning in the last year. Those who meet the screening criteria will be examined for prevalence of tooth decay using the DMFT (Decayed, Missing and Filled Teeth) index (Broadbent & Thompson, 2005). Those with the lowest scores (determined by a median split of scores) will be selected to participate in the study. Since consumption of a high sugar diet is associated with greater risk of oral disease, we will assess dietary intake of sugar from baked goods, candy, soft drinks and other beverages as well as discretionary sugar (added to coffee/tea and cereals).Test Samples:We will use an aqueous solution (0.75 mg/ml) of CPE (Ocean Spray, Lakeville MA), which contains 53.5% high MW proanthocyanidins, a concentration comparable to that used in a previous clinical study (Weiss, 2004). Pre-portioned samples will be aseptically packaged and dispensed to subjects at the beginning of each week of the study. Subjects will be instructed to rinse their mouth with samples for 30s and then spit it out.Procedures: A 2-week clinical trial is proposed in which 30 subjects (15 non-tasters and 15 super-tasters) will use 750 uM PACs extract as an oral rinse twice a day. Days 1-3 are control days when subjects rinse 2x/day with plain water; Days 4-14 are intervention days when subjects rinse with CPE twice/day. Salivary protein profiles will be assessed at the beginning and end of the intervention. Oral samples for microbiota analysis will also be taken at the beginning and end of the study.Microbial Profile Analysis:We will use 16S RNA sequencing, to identify and quantify the microbial communities in the salivary samples according to established methods (Roopchand et al., 2015; Zhang et al., 2018). Although this technique can only reveal gross differences at the phylum level, it is an appropriate first step for a pilot, feasibility study that would justify more in-depth analyses in the future.Expected outcomes: We expect that PROP Super-tasters will have lower abundance of pathogenic bacteria e.g. S. mutans and lower incidence of dysbiosis. We also expect that the CPE rinse will alter the pattern of microbial growth in favor of beneficial bacteria. Since this is an exploratory study, it is difficult to predict how the CPE rinse- intervention will affect the salivary protein profiles. Generally, we expect levels to rise in both groups relative to baseline, but we expect a more robust response in PROP non-tasters compared with PROP super-tasters. This difference is based on the premise that protein expression may already be at maximum levels with repeated exposure to CPE in super-tasters and may be more 'inducible' in non-tasters. This outcome would suggest that CPE rinsing provides specific benefits to non-tasters to raise levels of key proteins involved in oral health.