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Dicaffeoylquinic acid (DCQA) is a natural polyphenolic compound widely distributed in plants such as coffee beans, which possesses a range of pharmacological activities. Herein, is reported studies undertaken towards the first total synthesis of 3,5-DCQA conjugates. Two synthetic routes were investigated. The first route involves a seven step sequence beginning from quinic acid. The overall yield via this synthetic approach was 30%. The key steps involved in the sequence were a regioselective benzylation of the C-3-hydroxyl group followed by silyl protection of the C-1 and C-4 hydroxyl groups. Deprotection of the benzyl group by hydrogenolysis and opening of the lactone afforded the 3,5-diol. Esterification of the 3,5-diol with 3,4-tert-butyldimethylsilyl caffeoyl chloride afforded the di-ester. Removal of the protecting groups afforded 3,5-DCQA. The second route involved selective protection of the C-3-hydroxyl group with silyl followed by benzylation of the C-1 and C-3 hydroxyl groups. Saponification of the lactone ring followed by benzylation of the carboxylic acid gave the benzyl ester. Silyl deprotection afforded the 3,5-diol. The 3,5-diol was subsequently esterified by refluxing in toluene with commercially available Meldrum’s acid. In the final step, the synthesis of 3,5-DCQA was achieved by a Knoevenagel condensation of 3,4-dihydroxybenzaldehyde and a malonate ester of quinic acid. An efficient method for the synthesis of possible metabolites of quinic acid conjugates was also described. This protocol employs N-(4-methoxyphenyl)-trifluoroacetimidate glucuronyl as the donor. The key reaction in this sequence was the coupling of N-(4-methoxyphenyl)-trifluoroacetimidate glucuronyl with 4-hydroxy-3-methoxy-benzaldehyde.

Sunflower protein can be extracted at alkaline pH with sulfites or organic solvent de-phenolization of sunflower seed meals if greening is unwanted. This greening is promoted at alkaline pH when chlorogenic acid (CGA) oxidizes and reacts with free amine groups from amino acids, such as lysine. Thiol-containing dough conditioners: L-cysteine hydrochloride and reduced glutathione (GSH) were investigated as an alternative de-greening strategy to de-phenolization. Varying pH from 7 to 11 and concentration of 0.82 to 5.6 mM were randomly assigned by Response Surface Methodology (RSM) to evaluate the combined and additive greening inhibition effect of thiol and extraction pH. The powders with the highest greening were control (pH 8.93-9.3 and no added thiols) and pH 10.41 with 0.82 mM with thiols added. The powders with cysteine however had more browning than GSH. From RSM, the maximum greening inhibition was achieved with pH 8.71 and 4.23 mM cysteine and pH 8.51 and 3.78 mM GSH. Furthermore, fluorescence spectroscopy revealed that cysteine had a protective effect against alkaline denaturation, whereas GSH quenched fluorescence. Overall, the incorporation of thiol ingredients can be an alternative de-greening strategy for sunflower protein. These results could lead to extensive use of sunflower protein applications in non-allergenic and non-GMO plant-based meat alternatives or bakery products where greening is unwanted.

The two color-developing reactions that occur when soft pretzels are baked using sunflower flour (SFF) in aqueous alkali environment are chlorogenic acid (CGA)-quinone induced greening and Maillard browning. This study aimed to determine how CGA content in two different SFFs containing 45% and 55% protein (Heliaflor® 45 and 55, respectively) affected the formation of green trihydroxybenzacridine (TBA) and Maillard reaction products (MRPs) in soft baked pretzels. Pretzels were baked with five doughs prepared using a pre-blended gluten-free flour, consisting of sweet white rice flour, whole grain brown rice flour, potato starch, whole grain sweet white sorghum flour, tapioca flour, and xanthan gum: control (no SFF) and doughs replacing 3.65% and 7.30% GF flour with Heliaflor® (HF) 45 and 55. Pretzels were used for Hunter L, a, b color, and proximate analysis. Flour mixtures containing HF 45, HF 55, gluten free flour (GF) + HF 45, GF + HF 55 with 5% glucose, sucrose or sorbitol were also prepared. The supernatants from the centrifuged flour mixtures were used to quantify Schiff bases, CGA, melanoidins, and trihydroxybenzacridine (TBA) derivatives. The precipitates were dehydrated in a vacuum oven and FTIR analysis was used to identify changes that occurred in the secondary structures of proteins. Pretzels prepared with SFF contained CGA, whereas mixtures prepared with GF flour, without SFF, did not develop CGA and instead revealed the presence of non-CGA hydroxycinnamic acids (HCAs) such as caffeic, ferulic, and p-coumaric acid. The mixture containing HF 55 had the highest Schiff base, CGA, melanoidin, and green TBA content. There was no significant difference in CGA and MRPs between mixtures prepared using SFF containing 45% vs 55% protein or between the different sweeteners used. Greening in pretzels stored at ambient temperature increased 18 hours post-baking. The quantity of SFF used can be decreased to obtain the desirable shade of green color in the pretzels. The formation of MRPs such as excessive browning and Schiff bases can be decreased by decreasing the concentration of SFF to develop a gluten-free baked pretzel containing SFF for bakeries and restaurants.

Apples are one of the most commonly consumed fruits in America, and “an apple a day keeps the doctor away” is a well-known adage. The commercial and nutritional importance of apples has prompted interest in varietal improvement. However, progress is limited by a long juvenile period, which delays fruit evaluation for quality traits, such as phytochemical composition. To minimize this drawback, apple breeders have begun using marker-assisted selection (MAS) for some traits, but breeding strategies for fruit phytochemicals have yet to be developed.In response, we have developed an integrated genomic-metabolomic platform to better understand gene-phytochemical associations in breeding-relevant apple germplasm. Phytochemicals that are potentially health beneficial, contribute disease resistance, or improve fruit quality can be characterized using metabolomics, providing a foundation to study apple’s breeding potential. The platform is based on high-throughput genomic and metabolomic assessment of 173 unique apples, including members of three pedigree-connected families alongside diverse and wild selections. Single nucleotide polymorphism (SNP) data was obtained from the 20K SNP array for apple and integrated with metabolomic datasets from high-resolution mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy analyses of polar/semi-polar apple fruit extracts. Metabolite genome-wide association studies (mGWAS) were conducted with 11,165 SNPs for two LC-MS data sets of 4,000+ features each and an NMR data set of 756 bins. Novel schemes for prioritizing results from mGWAS indicated 519 (LC-MS (+)), 726 (LC-MS (-)), and 177 (NMR) significant marker-trait associations across the apple genome (LC-MS: p < .00001, NMR: p < .0001). These results were then sifted to select features to analyze with a more powerful pedigree-based analysis (PBA) in FlexQTL™ with 6,034 SNPs to identify metabolite quantitative trait loci (mQTL), genomic areas exerting genetic control over phytochemical production. An mQTL for chlorogenic acid was identified on the bottom of chromosome 17 across all three metabolomic data sets and was used as a proof-of-concept example to demonstrate the applicability of the platform. Determining gene-phytochemical relationships in apple will inform breeding and facilitate future MAS for improved nutrition along with attributes related to flavor and disease resistance etiology.

Heritage apple cultivars for cider-making are often distinguished by a high concentration of tannins (phenolic compounds), and/or acid. The phenolic content of some cider apples far exceeds that of white wine, however most cider fermentation practices are directly taken from white winemaking, not accounting for effects of high concentrations of phenolic compounds on yeast fermentation. The objective of this study was to determine the impact of ferulic acid, p-coumaric acid, and chlorogenic acid—at concentrations reported in apples—and their interactions with yeast assimilable nitrogen (YAN) on fermentation kinetics and cider aroma. Our hypothesis was that the phenolic compounds present in high-tannin cider apples would negatively impact fermentation kinetics, but not alter the aroma, and that added YAN would reduce these effects. Ferulic acid negatively affected fermentation performance (p < 0.05), but p-coumaric acid and chlorogenic acid did not. p-Coumaric acid led to the greatest changes in cider aroma. Differences were also detected for different concentrations of ferulic acid. Chlorogenic acid did not affect aroma. Yeast strain influenced fermentation performance and cider aroma. Finally, addition of exogenous YAN improved fermentation performance for the low concentration ferulic acid condition, but not for the high concentration. Adding YAN also changed cider aroma in the presence of p-coumaric acid.

Coffee is known as the most popular beverage after water. Arabica coffee accounts for 70% of the overall world coffee production. Coffee postharvest operations resulting in the production of green coffee, storage and roasting are important processing steps. Comparison of coffee postharvest treatments, storage and roasting temperatures were done to maximise yield of beneficial compounds. The study used the mechanically demucilaged coffee beans. The soaked and non-soaked parchment coffee samples were dried at 40 oC (20% RH), 50 oC (15% RH), 60 oC (15% RH) and 70 oC (10% RH). The soaked and non-soaked parchment coffee samples, dried at 40 oC (20 %RH), were selected to study effects of storage conditions (15 oC, 60% RH and 30 oC, 30% RH). After that, the samples were roasted and extracted. Moisture content, %weight loss and colour were measured to assure consistency of roasting levels of coffee samples. The analysis by HPLC showed highest concentration of chlorogenic acid, caffeine, trigonelline, α-tocopherol in the coffee beans which were non-soaked and stored at 15 oC and 60% RH for 6 month and roasted at light level (180 oC, 3 min). Positive correlation was found between total phenolic compounds content and the anti-oxidant activities (FRAP and ORAC). Moreover, the highest contents of cafestol and kahweol were found in green coffee. The soaked and dark roasted coffee samples received the highest score of consumer acceptance.

Flavonoids, such as anthocyanins, may be responsible for the health benefits of chokeberries, as they are present in large quantities in chokeberries and are potent antioxidant and anti-inflammatory agents. Despite these health properties, previous investigations on the bioavailability of flavonoids illustrate that little of the ingested amount reaches the bloodstream. This study investigated two factors that may help to explain these inconsistencies. First, storage of berry fruits and berry fruit products leads to extensive polymerization of their anthocyanins with procyanidins. Additionally, after consumption flavonoids may undergo metabolism into phenolic acids and subsequent conjugation to an extent that may explain their notable health properties despite their low absorption. Thus, the ultimate goal of this research was to determine the optimal storage conditions for retention of not only bioactive, but also bioavailable components in chokeberry juice that can provide cheaper alternatives to disease prevention. The effect of storage on the absorption and metabolism of flavonoids was investigated by identification and quantification of anthocyanins in the plasma and phenolic acids and their conjugates in the urine of rats after consumption of fresh (FCB) versus aged (ACB) chokeberry juice. Anthocyanins were not observed in the plasma of rats that received FCB nor ACB, reinforcing the limited bioavailability of anthocyanins. However, 3 phenolic acids, benzoylaminoacetic acid (BAA), benzoic acid (BA), and 3,4-dihydroxybenzoic acid (34HBA), were identified and excreted in higher quantities from rats that received chokeberry juice than rats fed de-ionized water (CTRL), indicating consumption of chokeberry juice may lead to the absorption of these compounds. Furthermore, consumption of FCB leads to higher excretion of BAA, a metabolite of chlorogenic acid and quercetin, than consumption of ACB. Further research on the metabolism and health properties of phenolic acids is necessary to understand the role of polyphenol-rich berries in chronic disease prevention.

Abstract: Potato peel, a waste generated from potato processing is a disposal problem. But, it is a good source of phenolic compounds, sugars, and glycoalkaloids. This study examines the subcritical water extraction of phenolics, glycoalkaloids and sugars from potato peel and compares it to conventional solvent extraction. Experiments were conducted in a batch stainless steel reactor at 6 MPa, 2 mL/min and 100 to 240˚C for 30-120 min. The results revealed that highest recoveries of phenolic compounds (81.23 mg/100 g; fw) and sugars (75 mg/g; fw) were obtained using subcritical water at 180°C and 30 min and at 160°C and 120 min, respectively. Low content of glycoalkaloids (1.19 mg/100 g, fw) was obtained using subcritical water. The yields of phenolics and sugars using subcritical water were 40 and 45% higher than using a conventional solvent extraction method. Therefore, subcritical water might be a good substitute to organic solvents such as methanol and ethanol to obtain functional ingredients from potato peel.