Survival of Listeria Strains and Shelf Life Determination of Fresh Blueberries (Vaccinium corymbosum) Treated with Cold Atmospheric Plasma.

Fresh blueberries are delicate, hand-picked, packaged, and refrigerated fruits vulnerable to spoilage and contamination. Cold atmospheric plasma (CAP) is a promising antimicrobial technology; therefore, this study evaluated the CAP treatment effect on acid-tolerant Listeria innocua and Listeria monocytogenes and evaluated changes in the quality of the treated fruit. Samples were spot-inoculated with pH 5.5 and 6.0 acid-adapted Listeria species. Samples were treated with gliding arc CAP for 15, 30, 45, and 60 s and evaluated after 0, 1, 4, 7, and 11 days of storage at 4 °C and 90% humidity for the following quality parameters: total aerobic counts, yeast and molds, texture, color, soluble solids, pH, and titratable acidity. CAP treatments of 30 s and over demonstrated significant reductions in pathogens under both the resistant strain and pH conditions. Sixty-second CAP achieved a 0.54 Log CFU g-1 reduction in L. monocytogenes (pH 5.5) and 0.28 Log CFU g-1 for L. monocytogenes (pH 6.0). Yeast and mold counts on day 0 showed statistically significant reductions after 30, 45, and 60 s CAP with an average 2.34 Log CFU g-1 reduction when compared to non-CAP treated samples. Quality parameters did not show major significant differences among CAP treatments during shelf life. CAP is an effective antimicrobial treatment that does not significantly affect fruit quality.

Effects of Extraction Methods on Phenolic Content, Antioxidant and Antiplatelet Activities of Tomato Pomace Extracts.

Aqueous and ethanolic extracts of tomato pomace were examined with the aim of optimizing the extraction process of compounds with cardioprotective activity. Once the results of the ORAC response variables, total polyphenols, °Brix, and antiplatelet activity of the extracts were obtained, a multivariate statistical analysis was performed using the Statgraphics Centurion XIX software. This analysis showed that the most relevant positive effects in the inhibition of platelet aggregation were 83 ± 2% when using the agonist TRAP-6, when the working conditions were the type of tomato pomace conditioning (drum-drying process at 115 °C), phase ratio (1/8), type of solvent (ethanol 20%), and type of extraction (ultrasound-assisted solid-liquid extraction). The extracts with the best results were microencapsulated and characterized by HPLC. The presence of chlorogenic acid (0.729 mg/mg of dry sample) was found, a compound that has a potential cardioprotective effect documented in various studies, in addition to rutin (2.747 mg/mg of dry sample) and quercetin (0.255 mg/mg of dry sample). These results show that the extraction efficiency of compounds with cardioprotective activity depends largely on the polarity of the solvent, thus playing an important role in the antioxidant capacity of the extracts of tomato pomace.

Effect of Encapsulation Processes by Freeze and Spray Drying on the Antioxidant Properties of Red Wine from cv. Listan Prieto and Syrah.

BACKGROUND: Wine antioxidants are linked to cardiovascular disease prevention, thus are highly valued by the healthy food market. The dehydration process removes alcohol and water from wine and allows it to extend its shelf life, while encapsulation can help preserve physical-chemical and antioxidant properties. Moreover, information on the effect of wine drying and encapsulation on non-anthocyanin phenolic compounds is limited in the literature. METHODS: Listan Prieto and Syrah (Vitis vinifera L.) wines were dehydrated and converted into powder by freezing and spray drying. Powdered wines were subjected to water activity, pH, soluble solids, color, and phenolic compounds analysis. RESULTS: Freeze-drying process produced powdered wines with higher pH than the spray-drying process. Powdered wines made by these processes presented similar water activity and soluble solids. Powdered wines did not show statistical differences in trans-resveratrol, hydrocinnamic acids, phloretin, kaempferol, and quercetin content according to their dehydration process. In addition, powdered wines significantly concentrated hydrocinnamic acid and quercetin when compared to non-dealcoholized and dealcoholized wine samples. CONCLUSIONS: The results suggest that the dehydration process does not negatively modify the characteristics of the wine, and it retains a significant concentration of phenolic compounds. Therefore, powdered wines have an interesting potential to be used as a natural source of antioxidants for food supplementation.

Consumer Response to Tomato Pomace Powder as an Ingredient in Bread: Impact of Sensory Liking and Benefit Information on Purchase Intent.

This study evaluated consumer acceptance and purchase intent (PI) for bread formulated with dried tomato pomace powder (DTPP). DTPP was used to substitute 5 or 10% by weight for a 50/50 mix of white and whole-wheat flour used in a control bread. Consumers (n = 231) evaluated sensory attributes and PI on the breads, which were produced and presented as slices from a typical commercial sandwich loaf. Before answering PI questions, panelists were presented with information regarding the DTPP ingredient. Some received information on nutritional quality, some on sustainability impact, some both, some neither. This approach allowed the impacts of those messages on PI to be tested, along with impact of liking, price, and other factors. PI was analyzed using a fractional logistic model. Statistically significant differences were observed in several sensory attributes, some favoring the DTPP ingredient with overall liking very similar for the 5% DTPP and control bread samples. Price and overall liking were highly significant variables effecting PI. DTPP proved to be an excellent ingredient to replace a portion of wheat flours to improve nutritional value of bread products. PRACTICAL APPLICATION: This study shows that dried tomato pomace powder (DTPP) has potential application as an ingredient, since it improved nutritional content, appearance, and color appeal of wheat bread. Furthermore, food producers who are considering the use of byproducts in their product formulations should be encouraged by the finding that informed consumers were as willing to purchase the bread with the ingredient, as they were to purchase a typical comparable sandwich bread without it. Furthermore, both a nutrition message and a sustainability message can increase PI for the bread containing the byproduct relative to their PI toward the control bread.

Effect of processing on quality attributes and phenolic profile of quince dried bar snack.

BACKGROUND: Fruit and vegetable processing can often alter and damage antioxidants. Phenolic compounds, which are major antioxidants in these products, can suffer dissociation and changes in their concentration. Quince is an excellent source of antioxidants, with health-improving potential for consumers. The phenolic profile (by ultra-high-performance liquid chromatography-mass spectrometry) and quality attributes (pH, soluble solids, acidity, water activity) were determined for processed quince products (fresh fruit puree, cooked puree and dried bars), in addition to the effect of puree cooking time (5, 10, 15 and 20 min). RESULTS: Soluble solids in purees averaged 14.4 °Brix and increased to 75 °Brix in bars, as did titratable acidity, reaching 1.5 g malic acid kg-1 fresh weight after 20 min of cooking at 120 °C. Quercetin, p-coumaric acid and trans-cinnamic acid were predominant in fresh fruit puree. Thermal processing significantly increased the concentration of p-coumaric acid, trans-cinnamic acid, apigenin and quercetin, and decreased gallic acid. This increase was 242%, on average, for all of them when comparing fresh fruit puree with bars on a fresh weight basis, demonstrating their concentration throughout the dehydration process during bar production. CONCLUSION: Although a minimum puree cooking time of 5 min was sufficient to obtain the highest concentration of most phenolics, p-coumaric acid showed a higher concentration after 20 min of cooking. © 2018 Society of Chemical Industry.

Effect of Storage on the Physico-Chemical and Antioxidant Properties of Strawberry and Kiwi Leathers.

Strawberry and kiwi leathers were used to develop a new healthy and preservative-free fruit snack for new markets. Fruit puree was dehydrated at 60 °C for 20 h and subjected to accelerated storage. Soluble solids, titratable acidity, pH, water activity (aw ), total phenolic (TP), antioxidant activity (AOA) and capacity (ORAC), and color change (browning index) were measured in leathers, cooked, and fresh purees. An untrained panel was used to evaluate consumer acceptability. Soluble solids of fresh purees were 11.24 to 13.04 °Brix, whereas pH was 3.46 to 3.39. Leathers presented an aw of 0.59 to 0.67, and a moisture content of 21 kg water/100 kg. BI decreased in both leathers over accelerated storage period. TP and AOA were higher (P ≤ 0.05) in strawberry formulations. ORAC decreased 57% in strawberry and 65% in kiwi leathers when compared to fruit puree. TP and AOA increased in strawberries during storage. Strawberry and Kiwi leathers may be a feasible new, natural, high antioxidant, and healthy snack for the Chilean and other world markets, such as Europe, particularly the strawberry leather, which was preferred by untrained panelists.