Pectin is an important polysaccharide with applications in foods, Pharmaceuticals, and a number of other industries. Its importance in the food sector lies in its ability to form gel in the presence of Ca2+ ions or a solute at low pH. Although the exact mechanism of gel formation is not clear, significant progress has been made in this direction. Depending on the pectin, coordinate bonding with Ca2+ ions or hydrogen bonding and hydrophobic interactions are involved in gel formation. In low‐methoxyl pectin, gelation results from ionic linkage via calcium bridges between two carboxyl groups belonging to two different chains in close contact with each other. In high‐methoxyl pectin, the cross‐linking of pectin molecules involves a combination of hydrogen bonds and hydrophobic interactions between the molecules. A number of factors—pH, presence of other solutes, molecular size, degree of methoxylation, number and arrangement of side chains, and charge density on the molecule— influence the gelation o...

Chemistry and uses of pectin--a review.

EFSA was asked to deliver a scientific opinion on acrylamide (AA) in food. AA has widespread uses as an industrial chemical. It is also formed when certain foods are prepared at temperatures above 120 °C and low moisture, especially in foods containing asparagine and reducing sugars. The CONTAM Panel evaluated 43 419 analytical results from food commodities. AA was found at the highest levels in solid coffee substitutes and coffee, and in potato fried products. Mean and 95th percentile dietary AA exposures across surveys and age groups were estimated at 0.4 to 1.9 μg/kg body weight (b.w.) per day and 0.6 to 3.4 μg/kg b.w. per day, respectively. The main contributor to total dietary exposure was generally the category ‘Potato fried products (except potato crisps and snacks)’. Preferences in home-cooking can have a substantial impact on human dietary AA exposure. Upon oral intake, AA is absorbed from the gastrointestinal tract and distributed to all organs. AA is extensively metabolised, mostly by conjugation with glutathione but also by epoxidation to glycidamide (GA). Formation of GA is considered to represent the route underlying the genotoxicity and carcinogenicity of AA. Neurotoxicity, adverse effects on male reproduction, developmental toxicity and carcinogenicity were identified as possible critical endpoints for AA toxicity from experimental animal studies. The data from human studies were inadequate for dose-response assessment. The CONTAM Panel selected BMDL10 values of 0.43 mg/kg b.w. per day for peripheral neuropathy in rats and of 0.17 mg/kg b.w. per day for neoplastic effects in mice. The Panel concluded that the current levels of dietary exposure to AA are not of concern with respect to non-neoplastic effects. However, although the epidemiological associations have not demonstrated AA to be a human carcinogen, the margins of exposure (MOEs) indicate a concern for neoplastic effects based on animal evidence. © European Food Safety Authority, 2015

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EFSA CONTAM Panel (EFSA Panel on Contaminants in the Food Chain), 2015. Scientific Opinion on acrylamide in food

Culturalable and non-culturable microorganisms naturally ferment majority of global fermented foods and beverages. Traditional food fermentation represents an extremely valuable cultural heritage in most regions, and harbors a huge genetic potential of valuable but hitherto undiscovered strains. Holistic approaches for identification and complete profiling of both culturalable and non-culturable microorganisms in global fermented foods are of interest to food microbiologists. The application of culture-independent technique has thrown new light on the diversity of a number of hitherto unknown and non-cultural microorganisms in naturally fermented foods. Functional bacterial groups ("phylotypes") may be reflected by their mRNA expression in a particular substrate and not by mere DNA-level detection. An attempt has been made to review the microbiology of some fermented foods and alcoholic beverages of the world.

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Review: Diversity of Microorganisms in Global Fermented Foods and Beverages

Non-dairy probiotic products.

Exploitation of vegetables and fruits through lactic acid fermentation

Antioxidant activities, phenolic and β-carotene contents of sweet potato genotypes with varying flesh colours

Sauerkraut fermentations rely upon selection of naturally occurring lactic acid bacteria by addition of 2.0% to 2.25% granulated sodium chloride (NaCl) to shredded cabbage. Excess brine generated is a waste product with high levels of organic material (BOD) and nonbiodegradable NaCl. The objective was to determine whether addition of Leuconostoc mesenteroides starter culture to reduced-salt cabbage fermentations would yield sauerkraut with reproducible and acceptable chemical composition and sensory qualities. Shredded cabbage was salted with 0.5%, 1.0%, or 2.0% NaCl (wt/wt) at 2 starter culture levels, none or L. mesenteroides strain LA 81, ATCC 8293 (10(6) CFU/g). Fermentation products were quantified by high-performance liquid chromatography, and pH was measured during the initial stages of fermentation and after 10 mo storage at 18 degrees C. A trained descriptive sensory panel used category scales to rate the flavor and texture of selected sauerkrauts. A modified Kramer shear test was used to measure firmness. Cabbage fermented with L. mesenteroides consistently resulted in sauerkraut with firm texture and reduced off-flavors across all salt levels (P < 0.05). Conversely, sauerkraut quality was highly variable, with softening and off-flavors occurring as salt concentrations were decreased in natural fermentations (P < 0.05). Fermentations were rapid, with a more uniform decline in pH when starter culture was added. L. mesenteroides addition to cabbage fermentations ensured that texture and flavor quality were retained, while allowing 50% NaCl reduction. Application of this technology to commercial sauerkraut production could improve the uniformity of fermentations and substantially reduce generation of nonbiodegradable chloride waste.

Effects of Leuconostoc mesenteroides starter culture on fermentation of cabbage with reduced salt concentrations.

Pressurized liquid extraction and quantification of anthocyanins in purple-fleshed sweet potato genotypes §

A procedure was developed and tested for fermentation of cucumbers at low concentrations of NaCl in experimental, anaerobic tanks. The procedure included washing of the cucumbers, use of a buffered cover brine composed of 0.045M calcium acetate, sodium chloride to equilibrate at 2.7% or 4.6%, Lactobacillus plantarum culture, and N2 purging to remove dissolved CO2. The fermentations were predominantly homofermentative, lactic acid accounting for 95% of the cucumber sugars fermented. Firmness retention of the fermented cucumbers during storage for 1 year was improved by heating packaged products to 69°C before storage, but firmness retention was acceptable in un-heated products.

Fermentation of Cucumbers in Anaerobic Tanks

Vegetables fermented by Lactobacillus plantarum with pH control were microbiologically stable during 12-months' storage in hermetically sealed jars at ca. 24°C provided all fermentable sugars were removed during fermentation, and the products were stored at pH 3.8 or below. Fermented green beans, cucumbers, red and gieen bell peppers, and green tomatoes were thus rendered microbiologically stable. Fermented red beets and carrots, which contained residual sucrose, underwent secondary fermentation. Calculated carbon recoveries of the fermented vegetables ranged from 74–146%.

R. L. Thompson

Papers

Antioxidant activities, phenolic and β-carotene contents of sweet potato genotypes with varying flesh colours

Effects of Leuconostoc mesenteroides starter culture on fermentation of cabbage with reduced salt concentrations.

Pressurized liquid extraction and quantification of anthocyanins in purple-fleshed sweet potato genotypes §

Fermentation of Cucumbers in Anaerobic Tanks

Storage Stability of Vegetables Fermented with pH Control