Effect of Postharvest Application of Aloe Vera Gel on Shelf Life, Activities of Anti-Oxidative Enzymes, and Quality of 'Gola' Guava Fruit.

Guava is an important climacteric fruits in terms of taste and aroma, which contains various vital nutrients such as minerals, carotenoids, ascorbic acid, and polyphenols. At ambient conditions, it exhibits a short shelf life, which makes it difficult for marketing and subsequent storage. Therefore, it is necessary to develop procedures to extend its shelf life and conserve quality. For this purpose, an aloe vera (AV) gel coating was assessed for its potential to enhance the shelf life of guava fruits. Guava fruits coated with AV gels (0, 20, 40, 60 and 80%, v/v) were evaluated for postharvest shelf life extension, changes in quality attributes, anti-oxidative activities, and flavonoid content when stored at ambient conditions (23 ± 2 °C and 70-75% relative humidity) for 12 days. The AV gel-treated fruits showed reduced increments in total sugar, malondialdehyde, and total carotene contents compared to untreated controls. AV gel-treated fruits exhibited higher contents of ascorbic acid, flavonoids (quercetin and rutin), and total phenolics in comparison to control fruits. Moreover, AV gel-treated fruits displayed greater activities of superoxide dismutase, catalase, and ascorbate peroxidase, along with higher antioxidant capacity and higher levels of total soluble solids, than untreated fruits. These results demonstrate that AV gel coating, especially at high concentrations, can be considered an eco-friendly and non-chemical substitute treatment for maintaining the postharvest quality of guava fruit.

Relationship of Arsenic and Lead in Soil with Fruit and Leaves of Apple Trees at Selected Orchards in Michigan.

ABSTRACT: Historically, lead arsenate pesticides were commonly used in fruit orchards. Residues of metals from this historical use can persist in soil for decades, which can result in potential risk for humans if they consume fruits grown on contaminated soil. This research was conducted to assess lead and arsenic levels in apples, leaves, and orchard soil where the apples were grown to determine the relationship between metal levels in fruits and fruit products with those in orchard soil. Soil and tree tissue samples were collected from several Michigan farms, and metal concentrations were quantified by using microwave extraction and inductively coupled plasma mass spectrometry. Soil samples were collected at depths of 0 to 20 cm and 20 to 40 cm at a distance of 1 m from the tree trunk. Fruit samples also were processed into juice and pomace fractions to assess the partitioning of arsenic and lead during juice processing. The lead concentration was significantly higher in topsoil (9.4 µg/kg) compared with subsoil (6.9 µg/kg), but the arsenic content did not differ between the two soil layers (P > 0.05). Lead concentrations in apple leaves were correlated with lead in topsoil (0 to 20 cm; P = 0.03). Concentrations of total arsenic in all juice samples were less than 1 µg/kg and showed less potential than lead for uptake and translocation to fruits. There was no significant relationship between soil arsenic content and total arsenic concentrations in juice, pomace, and leaf samples (P > 0.05). Results of this research indicate that lead and total arsenic concentrations in apples and apple products from these selected orchards in Michigan are unlikely to be impacted by the contamination of these metals in orchard soil.

Patulin surveillance in apple cider and juice marketed in Michigan.

Patulin is the most common mycotoxin found in apples and apple juices. The objective of this study was to determine the concentrations of patulin in (i) apple cider produced and marketed by Michigan apple cider mills during the fall seasons of 2002 to 2003 and 2003 to 2004 and (ii) apple juice and cider, including shelf-stable products, marketed in retail grocery stores in Michigan throughout 2005 and 2006. End product samples (n=493) obtained from 104 Michigan apple cider mills were analyzed for patulin concentration by using solid-phase extraction followed by high-performance liquid chromatography. Patulin was detected (> or =4 microg/liter) in 18.7% of all cider mill samples, with 11 samples (2.2%) having patulin concentrations of > or =50 microg/liter. A greater percentage of cider samples obtained from mills using thermal pasteurization contained detectable patulin (28.4%) than did those from mills using UV light radiation (13.5%) or no pathogen reduction treatment (17.0%). Among retail grocery store samples (n=159), 23% of apple juice and cider samples contained detectable patulin, with 18 samples (11.3%) having patulin concentrations of > or =50 microg/liter. The U.S. Food and Drug Administration (FDA) action level for patulin is 50 microg/kg. Some apple juice samples obtained from retail grocery stores had exceptionally high patulin concentrations, ranging up to 2700 microg/liter. Collectively, these results indicate that most apple cider and juice test samples from Michigan were below the FDA action level for patulin but that certain apple cider and juice processors have inadequate controls over patulin concentrations in final products. The industry, overall, should focus on improved quality of fruit used in juice production and improve culling procedures to reduce patulin concentrations.

High sucrose diets promote intestinal epithelial cell proliferation and tumorigenesis in APC(Min) mice by increasing insulin and IGF-I levels.

Epidemiological studies report that high sucrose consumption is associated with increased risk of colon cancer. One hypothesis is that this association is mediated by elevated circulatory insulin and IGF levels promoting intestinal proliferation. To test this hypothesis, APC(Min) mice and their wild type littermates were fed, starting at 4 wk of age, sucrose or cornstarch as the sole carbohydrate source in the absence or presence of low levels of dietary sulindac for 10 or 16 wk, respectively. APC(Min) mice fed sucrose had an increased tumor number in the proximal third of the small intestine in both studies and a higher incidence of papillary colon tumors in the 16-wk feeding study (P < or = 0.05). Mice fed sucrose (relative to cornstarch) had higher body weights and greater Ki67-labeling indexes in colonic epithelium than mice fed cornstarch in both feeding studies (P < or = 0.05). Furthermore, mice fed sucrose had higher serum glucose and liver IGF-I mRNA concentrations (P < or = 0.05) and tended to have higher serum insulin levels (P = 0.08). These results support the hypothesis that high dietary sucrose intake promotes intestinal proliferation and tumorigenesis by increasing circulating levels of insulin and IGF-I.

Dietary carbohydrate source alters gene expression profile of intestinal epithelium in mice.

High-sucrose consumption is associated with increased risk of human colon cancer. Our previous research indicated that high-sucrose diets (vs. cornstarch) promote intestinal epithelial cell proliferation and tumorigenesis as well as increase serum glucose and hepatic IGF-I mRNA levels in APC(Min) mice. To examine the role of functional pathways, in particular of IGF-I signaling, in sucrose-induced intestinal epithelial cell proliferation and tumorigenesis, we examined the effects of dietary carbohydrate source (sucrose vs. cornstarch) on gene expression in the intestinal epithelium using cDNA microarray and quantitative RT-PCR analysis. Dietary carbohydrate source significantly (P < 0.05) altered mRNA expression of 109 known genes in the small intestinal epithelium, including many involved in metabolic pathways. Consumption of high-sucrose diets altered expression levels of genes involved in cell adhesion, cell cycle control, and transduction signaling, consistent with increased risk of intestinal tumorigenesis. High-sucrose intake also affected expression of genes involved in IGF-I signaling, including upregulating IGF-II and downregulating IGFBP3, which supports our hypothesis that IGF-I signaling could play a role in intestinal epithelial cell proliferation and tumorigenesis promoted by high-sucrose consumption.

Dietary anthocyanin-rich tart cherry extract inhibits intestinal tumorigenesis in APC(Min) mice fed suboptimal levels of sulindac.

A promising approach for cancer chemoprevention might be a combination therapy utilizing dietary phytochemicals and anticarcinogenic pharmaceuticals at a suboptimal dosage to minimize any potential adverse side effects. To test this hypothesis, various dosages of anthocyanin-rich tart cherry extract were fed in combination with suboptimal levels of the nonsteroidal anti-inflammatory drug sulindac to APCMin mice for 19 weeks. By the end of the feeding period, fewer mice that were fed the anthocyanin-rich extract in combination with sulindac lost more than 10% of body weight than mice fed sulindac alone. Mice that were fed anthocyanin-rich extract (at any dose) in combination with sulindac had fewer tumors and a smaller total tumor burden (total tumor area per mouse) in the small intestine when compared to mice fed sulindac alone. These results suggest that a dietary combination of tart cherry anthocyanins and sulindac is more protective against colon cancer than sulindac alone.

Tart cherry anthocyanins inhibit tumor development in Apc(Min) mice and reduce proliferation of human colon cancer cells.

Anthocyanins, which are bioactive phytochemicals, are widely distributed in plants and especially enriched in tart cherries. Based on previous observations that tart cherry anthocyanins and their respective aglycone, cyanidin, can inhibit cyclooxygenase enzymes, we conducted experiments to test the potential of anthocyanins to inhibit intestinal tumor development in Apc(Min) mice and growth of human colon cancer cell lines. Mice consuming the cherry diet, anthocyanins, or cyanidin had significantly fewer and smaller cecal adenomas than mice consuming the control diet or sulindac. Colonic tumor numbers and volume were not significantly influenced by treatment. Anthocyanins and cyanidin also reduced cell growth of human colon cancer cell lines HT 29 and HCT 116. The IC(50) of anthocyanins and cyanidin was 780 and 63 microM for HT 29 cells, respectively and 285 and 85 microM for HCT 116 cells, respectively. These results suggest that tart cherry anthocyanins and cyanidin may reduce the risk of colon cancer.