Nutritional and nutraceutical comparison of Jamaican Psidium cattleianum (strawberry guava) and Psidium guajava (common guava) fruits

Psidium cattleianum (strawberry guava) is one of many underutilised edible fruits that grow wild in Jamaica, and could potentially be commercially exploited to yield health and economic benefits. In this study, the total phenolics, proximate contents, and antioxidant, anti-inflammatory, and antimicrobial activities of P. cattleianum and P. guajava (common guava), a well-known species, were compared. Strawberry guavas were found to be superior to common guavas in antioxidant and antimicrobial activities, total phenolics and vitamin C content. They also possessed relatively high fibre content (24.9%). The hexane and ethyl acetate extracts of strawberry guavas showed cyclooxygenase-2 enzyme inhibitory activities of 18.3% and 26.5%, respectively (250 μg/mL), indicating anti-inflammatory activity. The EtOAc and MeOH extracts of P. guajava showed 56.4% (COX-2) and 44.1% (COX-1) inhibitory activity, respectively. Additionally, nine compounds were isolated from strawberry guava fruits, some of which demonstrated anti-inflammatory activity. These results indicate that strawberry guavas are beneficial for health.     

Effect of ultrasound irradiation on some freezing parameters of ultrasound-assisted immersion freezing of strawberries

In this study, the effect of ultrasound irradiation temperature and ultrasound intensity on the freezing and nucleation in strawberry samples was studied. The application of ultrasound irradiation at different temperatures was able to induce nucleation at lower degree of supercooling compared to the control samples. The achieved degree of supercooling in the ultrasound irradiated strawberries was linearly correlated to the ultrasound irradiation temperature. At the ultrasound irradiation temperature of −1.6 °C, the characteristic freezing time (CFT) was significantly shorter than that in the control sample (p < 0.05). The application of ultrasound at higher intensities was found to effectively shorten the CFT. The degree of supercooling in ultrasound irradiated samples was not linearly correlated to ultrasound intensity. In conclusion, the combination of ultrasound irradiation temperature and intensity can be effective in controlling nucleation and freezing processes of perishable fruits such as strawberry.     

Quality characteristics of strawberry genotypes at different maturation stages

The chemical composition and quality characteristics of nine promising hybrids and two varieties (“Osmanli” and “Camarosa”) of strawberries were evaluated for their quality attributes during ripening. Main soluble sugars, carboxylic acids, organic acids and ascorbic acid of experimental varieties were separated, identified and quantified using high-performance liquid chromatography with diode array spectroscopic and refractive index detections. Titratable acidity (TA), pH, total soluble solids (TSS) and TSS/TA ratio and their correlations were determined at ripe maturation stages for the 11 genotypes. Hybrid no. 11, a new strawberry cultivar, had desired fruit quality characteristics similar to Osmanli, which has a pleasant taste and is popular in Turkey.     

影响草毒果汁红色素变化的因子研究

通过试验对草莓果汁在加工及继后贮藏过程中,影响红色素变化的因子进行了研究。结果表明,迅速加热果实温度到60℃,有利于提高果汁中红色素含量;向果汁中分别加入0.1%~0.4%的抗坏血酸、酒石酸和柠檬酸对果汁具有明显的增色作用;而加入1.0%~15.0%的葡萄糖和蔗糖对果汁颜色没有影响;调整果汁pH值到4.0以下有助于保持果汁的固有颜色;采用低温避光贮存果汁可延缓草莓果汁红色素的降解。     

The effect of soy protein concentrate addition on the physical, chemical, and sensory properties of strawberry flavored ice cream

The effect of soy protein concentrate (0, 1.5, 3, and 4.5%) on the physical, chemical, and sensory properties of strawberry flavored (0, 0.01 and 0.02%) ice cream samples was examined. All samples were analyzed for pH, titratable acidity, total solids, nitrogen, fat, ash, overrun, viscosity, meltdown, Hunter L-, a-, b- values, flavor, body and texture, and appearance. Substituting soy protein concentrate (SPC) in ice cream formula for non-fat dry milk (NFDM) positively influenced the nitrogen content, viscosity values, and melting and appearance properties of the ice cream samples while overrun values and flavor scores were negatively affected. SPC could be incorporated into the ice cream formula in the range of 1.5–3% devoid of significantly diminishing the physical, chemical, and sensory properties.     

超高压对胡萝卜-草莓复合汁中酶和微生物的影响

目的：为利用超高压技术加工鲜榨果汁提供依据；方法：采用超高压处理鲜榨胡萝卜-草莓复合汁，发现不同压力、保压时间对复合果汁中POD、PPO和LOX酶的活性及其微生物的致死作用不同；结果：在200，300，400，500，600MPa分别处理20min时，POD最耐压，LOX对压力最敏感，其中600MPa下POD、PPO和LOX分别失活46．15％、52％和77．24％。在400MPa、20min处理的复合汁中大肠杆菌≤3MPN／100mL，细菌总数≤10CFU／mL。     

Effect of nitric oxide on ethylene production in strawberry fruit during storage

Strawberry is a non-climacteric fruit, with low ethylene production rate after harvest. Its response to nitric oxide (NO), which can be released from sodium nitroprusside (SNP), was studied. We have examined the effect of 1.0, 5.0 and 10.0 μmol l⁻¹ SNP aqueous solution on ethylene production, respiration rate, 1-aminocyclopropane-1-carboxylic acid (ACC) content and the activities of ACC synthase and ACC oxidase in post-harvest strawberry (“Fengxiang”). The most remarkable effect was obtained with 5 μmol l⁻¹ SNP aqueous solution, which significantly inhibited ethylene production, respiration rate, the activity of ACC synthase and reduced the content of ACC, but did not significantly affect the activity of ACC oxidase. SNP at 10 μmol l⁻¹ harmed the fruits; 1 μmol l⁻¹ SNP was too low to significantly extend strawberry storage life. It was suggested that NO could decrease ethylene output, through inhibiting ACC synthase activity reducing ACC content.     

Potential of berry extracts to control foodborne pathogens

Globally, foodborne diseases continues to be a serious public health problem. Among the infectious bacteria implicated in these diseases, non-typhoidal Salmonella enterica (NTS) serovars are the major cause of hospitalization and death, followed by Campylobacter, Clostridium perfringens, Escherichia coli O157:H7, and Listeria monocytogenes. In addition, the emergence and spread of antibiotic-resistance strains among these bacteria is becoming a worldwide food safety issue. This rise of resistance led to the restriction of antibiotics use in animal productions in the European Union and application of a possible similar action in the North America. To limit the use of antibiotics in agricultures while satisfying the consumer demands, effective alternative approaches to maintain the animal health and productivity as well as to preserve food need to be explored. In this context, the plant-derived antibacterial compounds could provide novel approaches to control pathogenic bacteria in food industry. In this paper, we review the potential of three different berries (cranberries, blueberries and strawberries) extracts, as alternative antibacterial products against foodborne pathogens. These extracts show various antimicrobial activities against Gram positive (Listeria, Staphylococcus aureus, and Clostridium perfringens) and Gram negative (Salmonella enterica, E. coli and Campylobacter spp.) bacteria. Berry extracts seem to have a pleotropic mode of actions against foodborne bacteria. Several studies on proanthocyanidins from cranberry demonstrated its bactericidal action through anti-adhesion activities and free iron sequestration. Blueberry phenolics were reported to decrease cell auto-aggregation, motility and affect the cellular hydrophobicity. Similar action was observed with strawberry extracts due to their immobilizing capacity. Key research gaps include the effects of processing, bioavailability and detail mechanisms of action of berry compounds.     

新型有机肥的氮素在土壤中的转化及其对草莓生长和品质的影响

土壤中硝态氮和铵态氮的含量直接影响着作物的生长和品质。通过田间试验研究了不同有机肥料氮素在土壤中的转化及其对草莓生长和果实品质的影响。结果表明,施用有机肥可以提高草莓苗期土壤硝态氮的比例,硝铵比值大于尿素处理,同时有机肥处理硝铵比值从苗期至盛花期呈下降趋势,但尿素处理则表现为上升的趋势,而花序现蕾期土壤硝铵比的降低,有利于植株花蕾的形成,因此土壤硝铵比值的变化趋势一定程度上决定着草莓的产量和品质。在等量施用氮素养分的条件下,施用有机肥料均较尿素更能促进草莓生长发育和增加草莓产量。施用有机肥对草莓品质的改善作用也优于尿素,果实中糖/酸比值较无肥区提高23.7%-28.7%,较尿素区提高16.5%-21.2%。     

Kinetic study on the thermal and pressure degradation of anthocyanins in strawberries

The degradation of anthocyanins (pelargonidin-3-glucoside) in a strawberry paste during high-temperature/high-pressure treatments was investigated over a temperature range of 80–130 °C and a pressure range of 200–700 MPa, compared to 0.1 MPa. A first-order kinetic model fitted well to all data. At constant pressure, anthocyanin concentration decreased as a function of time and the degradation was accelerated at higher temperatures. At constant temperature, anthocyanins were more rapidly degraded as the pressure increased, but the effect of increasing pressure was smaller than the effect of increasing temperature. Temperature dependence of the degradation rate constants, described by the Arrhenius equation, was higher at atmospheric pressure than at elevated pressures, where all activation energies were comparable. Activation volumes, estimated by the Eyring equation, demonstrated a small pressure dependence of the reaction rate constants. Finally, a model to describe the combined temperature–pressure dependence of the degradation rate constants was proposed.