Male C57BL/6J mice received diets with either 10% of calories from fat (LF) or a high-fat diet [45% (HF45) or 60% (HF60) calories from fat] for 92 days (expt 1) or 70 days (expt 2). These were given with or without freeze-dried powders from whole blueberries (BB) or strawberries (SB) (expt 1) or purified anthocyanin extracts from BB or SB (expt 2). Body composition was determined utilizing Echo MRI. Berries added to the LF diet did not alter weight gain, final body weights, body fat, or protein (percent body weight) or diet (grams) or energy (kilocalories) intake. However, in both HF45-and HF60-fed mice, weight gain, final weights, body fat (percent), and epididymal fat weights increased and body protein decreased (p < 0.01) compared to LF mice. In mice fed HF45 diet plus BB, body weight gains, body fat (percent of BW), and epididymal fat weights were significantly greater than those in the HF45-fed controls, whereas weights of mice fed SB HF were similar to those of HF controls. SB or BB feeding did not alter glucose tolerance, although glucose tolerance decreased with age and in HF45 versus LF mice. Baseline plasma glucose was lower in SB-versus HF45-fed mice. After 8 weeks, mice fed the HF60 diet plus purified anthocyanins from BB in the drinking water had lower body weight gains and body fat than the HF60-fed controls. Anthocyanins fed as the whole blueberry did not prevent and may have actually increased obesity. However, feeding purified anthocyanins from blueberries or strawberries reduced obesity.

Blackberries ( Rubus sp.) were evaluated by high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) to identify the ellagitannins present in flesh, torus (receptacle tissue), and seeds. Most ellagitannins were present (or detectable) only in seed tissues. Ellagitannins identified by HPLC-ESI-MS in the seeds included pedunculagin, casuarictin/potentillin, castalagin/vescalagin, lambertianin A/sanguiin H-6, lambertianin C, and lambertianin D. For several of the ellagitannins, isomeric separation was also obtained. The MALDI-TOF-MS analysis was primarily utilized to evaluate and identify high molecular mass (>1000 Da) ellagitannins. The MALDI analysis verified the presence of the ellagitannins identified by HPLC-ESI-MS including lambertianin A/sanguiin H-6, lambertianin C, and lambertianin D, but the analysis also indicated the presence of several other compounds that were most likely ellagitannins based on the patterns observed in the masses (i.e., loss or addition of a gallic acid moiety to a known ellagitannin). This study determined the presence of several possible isomeric forms of ellagitannins previously unidentified in fruit and presents a possible analytical HPLC method for the analysis of the major ellagitannins present in the fruit.

Male C57BL/6 mice received diets with either 10% of kcal from fat, or a high fat diet [45% (HF45) or 60% (HF60) kcal from fat]. Diets were prepared with or without freeze-dried powders (10%) from whole blueberries (BB), strawberries (SB), Concord grape or black raspberry. In the 2nd study, purified anthocyanins (ACNs) from SB or BB were added to the drinking water of the treatments fed the HF60 diet. In Study 1, serum triglycerides were increased by feeding the HF45 diet but were elevated further when black raspberry or BB was included in the HF45 diet. Liver total lipids and triglycerides were increased in mice fed HF45 diet and inclusion of any of the berry powders in the HF45 diet did not alter concentrations compared to HF45 controls. In the 2nd study, mice fed the HF60 diet plus purified ACNs from BB in the water had lower body weight gains and body fat than the HF60 fed. Serum cholesterol and triglyceride levels were elevated with the HF60 diet and decreased to control levels when ACNs from either SB or BB were included in the drinking water. Serum leptin levels were consistently decreased to control low fat levels in those ACN treatments in which measures of body fat were decreased. Administering purified ACNs from BB and strawberry via drinking water prevented the development of dyslipidemia and obesity in mice, but feeding diets containing whole berries or purple corn (PC) ACNs did not alter the development of obesity.

Blackberries are a rich source of polyphenolics, particularly anthocyanins, that may contribute to the reduced risk of chronic disease; however, as with most berries, the fresh fruit are only seasonally available. With most of the blackberries consumed as frozen or in thermally processed forms after long-term storage, the purpose of this study was to evaluate the effects of processing and 6 months of storage on the anthocyanins and antioxidant capacity of blackberries that were individually quick-frozen (IQF), canned-in-syrup, canned-in-water, pureed, and juiced (clarified and nonclarified). Monomeric anthocyanins, percent polymeric color, and antioxidant capacity by oxygen radical absorbance capacity (ORAC FL) and photochemiluminescence (PCL) were determined postprocessing (1 day) and after 1, 3, and 6 months of storage. Processing resulted in increases in polymeric color values (up to 7%) and losses in monomeric anthocyanins (up to 65%). For most products, processing also resulted in losses in antioxidant capacity (by ORAC FL and PCL). Storage at 25 degrees C of all processed products resulted in dramatic losses in monomeric anthocyanins with as much as 75% losses of anthocyanins throughout storage, which coincided with marked increases of percent polymeric color values of these products over 6 months of storage. There were no changes in ORAC FL or PCL for processed products throughout long-term storage. No significant changes in antioxidant capacity or anthocyanin content were observed in IQF fruit during long-term storage at -20 degrees C.

Changes in blackberry ellagitannin composition in response to juicing (clarified and nonclarified), pureeing, canning (in water or syrup), and freezing as well as changes in processed products during 6 months of storage were investigated. Canning, pureeing, and freezing had little effect on ellagitannins, but processing berries into nonclarified and clarified juices resulted in total ellagitannin losses of 70 and 82%, respectively, due to removal of ellagitannin-rich seeds in the presscake. Minimal changes in total ellagitannin content were observed during storage of thermally processed products, but compositional changes indicative of ellagitannin depolymerization were apparent. The ellagitannin content and composition of frozen berries remained stable over 6 months of storage. Ellagitannins are well retained in canned, pureed, and frozen blackberries, but methods are needed to prevent losses during juice processing and/or exploit the ellagitannin-rich coproducts.