Synergistic Effect of Mandarin Peels and Hesperidin with Sodium Nitrite against Some Food Pathogen Microbes

Food preservatives such as NaNO2, which are widely used in human food products, undoubtedly affect, to some extent, human organs and health. For this reason, there is a need to reduce the hazards of these chemical preservatives, by replacing them with safe natural bio-preservatives, or adding them to synthetic ones, which provides synergistic and additive effects. The Citrus genus provides a rich source of such bio-preservatives, in addition to the availability of the genus and the low price of citrus fruit crops. In this study, we identify the most abundant flavonoids in citrus fruits (hesperidin) from the polar extract of mandarin peels (agro-waste) by using spectroscopic techniques, as well as limonene from the non-polar portion using GC techniques. Then, we explore the synergistic and additive effects of hesperidin from total mandarin extract with widely used NaNO2 to create a chemical preservative in food products. The results are promising and show a significant synergistic and additive activity. The combination of mandarin peel extract with NaNO2 had synergistic antibacterial activity against B. cereus, Staph. aureus, E. coli, and P. aeruginosa, while hesperidin showed a synergistic effect against B. cereus and P. aeruginosa and an additive effect against Staph. aureus and E. coli. These results refer to the ability of reducing the concentration of NaNO2 and replacing it with a safe natural bio-preservative such as hesperidin from total mandarin extract. Moreover, this led to gaining benefits from their biological and nutritive values.

Antibacterial Activity and Mechanism of Linalool against Shewanella putrefaciens

The demand for reduced chemical preservative usage is currently growing, and natural preservatives are being developed to protect seafood. With its excellent antibacterial properties, linalool has been utilized widely in industries. However, its antibacterial mechanisms remain poorly studied. Here, untargeted metabolomics was applied to explore the mechanism of Shewanella putrefaciens cells treated with linalool. Results showed that linalool exhibited remarkable antibacterial activity against S. putrefaciens, with 1.5 µL/mL minimum inhibitory concentration (MIC). The growth of S. putrefaciens was suppressed completely at 1/2 MIC and 1 MIC levels. Linalool treatment reduced the membrane potential (MP); caused the leakage of alkaline phosphatase (AKP); and released the DNA, RNA, and proteins of S. putrefaciens, thus destroying the cell structure and expelling the cytoplasmic content. A total of 170 differential metabolites (DMs) were screened using metabolomics analysis, among which 81 species were upregulated and 89 species were downregulated after linalool treatment. These DMs are closely related to the tricarboxylic acid (TCA) cycle, glycolysis, amino acid metabolism, pantothenate and CoA biosynthesis, aminoacyl-tRNA biosynthesis, and glycerophospholipid metabolism. In addition, linalool substantially affected the activity of key enzymes, such as succinate dehydrogenase (SDH), pyruvate kinase (PK), ATPase, and respiratory chain dehydrogenase. The results provided some insights into the antibacterial mechanism of linalool against S. putrefaciens and are important for the development and application of linalool in seafood preservation.

Antimicrobial Activity of Plant Essential oils and TheirEmerging Role in Food Sector

Abstract-Foodpreservativesareusedtoincrease the shelf life of food and to maintain the quality for longer time. Natural methods of preservationusuallyaimtoexcludeair,moisture, and microorganisms, or to provide environments in which organisms that might 25cause spoilage cannot survive. In the last scenario, no herbal Ayurvedic preservative had been considered with respect to the use of chemical preservative. Increasing demands for naturalandpreservativefreecompoundspromoted an idea of the replacementof synthetic preservatives withessential oilshaving antimicrobial properties.Essentialoilsfrommedicinalplantsarepotentialsourceofnovelantimicrobialcompounds especially against food spoilage pathogens. The aim of this project was to compare the antimicrobial activity of essential oils collected from Lemongrass (Cymbopoga ncitratus), Clove (Syzygiumaromaticum) and Tulsi (Ocimum sp.) against food spoilage organisms.In this study the essential oil of Lemongrass, Clove and Tulsi were investigated for its activity against Gram negative bacteria Escherichia coli, Gram positive bacteriaMicrococcusluteus, Staphylococcus aureus andBacillus cereus, yeast Candida albicans and fungusAspergillus niger, Chaetomium globosum and Penicilliumfuniculosumusingagarwelldiffusion method. The antimicrobial activity was evaluated by measuring the zone of inhibition. The oils at 30% concentration completely/partially inhibited the growth of foodspoilagepathogens.Thestrongestinhibition activity was observed in Lemongrass oil against all the test organisms; thus it was found more effective as compared to Clove oil and Tulsi oil.The successful effectiveness of Lemongrass oil could also play a major role in replacing the chemical preservative.

EFFECT OF GINGER EXTRACT ON THE VIABILITY OF LACTIC ACID BACTERIA AND SENSORY CHARACTERISTICS OF DAIRY YOGHURT AND SOY YOGHURT

Yoghurt is usually produced from cow milk which is unsuitable for vegetarian diet. Chemical preservative used for its preservation may have adverse effect on the lactic acid bacteria. This research was designed to evaluate the effect of ginger extract on the viability of lactic acid bacteria, physico-chemical property and sensory attributes of bio preserved functional yoghurt produced from dairy milk and soy milk during storage at refrigerated temperature. The result obtained showed that yoghurt produced from soy milk (5.67 – 7.52 CFU/ml) had higher lactic acid bacteria count than yoghurt from dairy milk (4.71 – 7.31 CFU/ml) throughout the period of storage. Ginger extract was more active against fungi in dairy yoghurt than (0 - 5.09 CFU/ml) soy yoghurt (0 – 5.29 CFU/ml). The pH was generally lower in dairy yoghurt (4.29 - 4.67) than soy yoghurt (4.69 – 5.14) while the titratable acidity was higher in dairy yoghurt (1.30 – 2-01%) than soy yoghurt (0.7 – 1.54%). Addition of ginger extract improved the texture and flavour of soy yoghurt. It is therefore suggested that functional yoghurt with good sensory attributes can be produced from soy milk and dairy milk using ginger extract as bio-preservative.

Enhancement of Enduracidin Accumulation from Sweet Sorghum Juice via Alleviation of Oxidative Damage in Streptomyces Fungicidicus M30

Background: Sweet sorghum juice is the preferred feedstock for enduracidin production, but the fermentation efficiency still need to be further enhanced. Oxygen-mediated microbial cell damage is an effective way to boost cell growth and metabolite accumulation in aerobic fermentation. However, this strategy on enduracidin production from sweet sorghum juice has not been reported yet. Results: In this study, enduracidin production titer was significantly enhanced when 90 mM Vitamin C was added at 4 d of fermentation. The enhanced T-AOC and antioxidant enzyme activities may help to further understand the mechanism of Vitamin C effect on regulation of enduracidin accumulation in S. fungicidicus M30. The effects of chemical preservative methyl paraben on cell growth and enduracidin production were also evaluated, and 0.04 g/L of methyl paraben had no significant inhibitory effect on cell growth and enduracidin production, indicating that the concentrated sweet sorghum juice assisted by methyl paraben for a long-term storage can be used as the substrate for enduracidin production effectively. Finally, based on the group with 0.04 g/L of methyl paraben and 90 mM Vitamin C, a final enduracidin concentration of 1.14 g/L was achieved from clarificated sweet sorghum juice by M30 strain. Conclusions: This work provided a promising strategy to enhance enduracidin production using sweet sorghum juice via adding the antioxidant to boost antioxidant capacity in S. fungicidicus.

In vitro antimicrobial activity of Lemon grass oil by MIC and agar well diffusion method

Abstract-Foodpreservativesareusedtoincrease the shelf life of food and to maintain the quality for longer time. In the last scenario no herbal ayurvedic preservative had been considered with respect to the use of chemical preservative. Due to increasing demands for naturalandpreservativefreecompoundspromoted an idea of the replacement of synthetic preservatives with essential oils of antimicrobial properties.Essentialoilsfrommedicinalplantsarepotentialsourceofnovelantimicrobialcompounds especially against food spoilage pathogens. The aim of this project was to study antimicrobial activity of essential oil from Lemongrass (Cymbopogan citratus)oil against food spoilage organisms Escherichia coli, Micrococcus luteus, Staphylococcus aureus andBacillus cereus and fungus Aspergillus brasilliensis, Candida albicans, Chaetomium globosum and Penicillium funiculosumusing agar well diffusion method. The antimicrobial activity was evaluated by measuring the zone of inhibition. The oil at30% concentration completely/partially inhibited the growth of foodspoilagepathogens.Thesuccessfuleffectiveness of Lemon grass oil could also play amajorroleinreplacingthechemicalpreservative.

Efficacy of Purified Bacteriocin of “Brevibacillus laterosporus TK3” against Listeria monocytogenes and Staphylococcus aureus in Chicken

In the present investigation the biopreservative effect of bacteriocin of Brevibacillus laterosporus TK3 was investigated in raw chicken. Bacteriocin producing strain has been isolated from “Tatwakhar”- a flour prepared from seeds of Indian Horse Chestnut (Aesculus indica). Bacteriocin of Brevibacillus laterosporus TK3 showed strong antagonism against food spoilage/pathogenic bacteria viz. Listeria monocytogenes and Staphylococcus aureus. The bacteriocin was purified and molecular weight of this novel bacteriocin was found to be 6 kDa. This purified bacteriocin with specific activity 34,482.0 AU/mg was applied in raw chicken and minced chicken against L. monocytogenes and S. aureus which showed the positive results in controlling the growth of these deadly pathogens. Purified bacteriocin was found successful in controlling the growth of L. monocytogenes up to 7th day which is almost at par with the results achieved with chemical preservative i.e. sodium nitrite. Further, purified bacteriocin restricted the growth of S. aureus up to 5th day whereas chemical preservative was able to control the growth of S. aureus up to 3rd day. The results found in these experiments deal with application of bacteriocin as biopreservative in chicken as an alternative to chemical preservative are quite encouraging and satisfactory.

Effectiveness of preserving agents in alfalfa ensiling

Проведены исследования по силосованию люцерны, убранной в ранней фазе вегетации, с использованием биологического и химического консервантов. Цель работы — определить эффективность использования химического и биологического консервантов при силосовании люцерны. Исходным сырьём для проведения исследований служила зелёная масса люцерны в фазе бутонизации. Консерванты вносили при закладке массы из расчёта 5 л/т. В качестве консервантов использовали экспериментальные препараты: биологический — на основе смеси молочнокислых и пропионовокислых бактерий, химический — на основе смеси органических кислот. Интенсивность протекания биохимических процессов определяли в течение месяца после закладки посредством учёта воды, вытесненной газами. Установлено, что консерванты снижают интенсивность биохимических процессов, протекающих при силосовании. По сравнению с контролем объём выделившихся газов при внесении биологического консерванта оказался меньше на 15,3%, с использованием химического консерванта — в 3,2 раза. Энергетическая ценность исходного сырья составила 2,26 МДж обменной энергии, силоса без консерванта — 1,84, с биологическим и химическим консервантами — 1,96 и 2,06 МДж обменной энергии соответственно. В контрольном варианте потери органического вещества по сравнению с исходным сырьём составили 14,7%, что больше в 1,24 раза, чем в варианте с биологическим консервантом и в 4,17 раза — с химическим консервантом. Примерно такая же тенденция отмечена и по потерям протеина и БЭВ. В расчёте на 1 т силоса применение биологического консерванта позволило дополнительно получить 119,6 МДж обменной энергии, с химическим консервантом — 246,4 МДж обменной энергии по сравнению с контролем. При скармливании 1 т консервированного корма молочным коровам дополнительно можно получить 13,3 и 27,4 кг молока, а дополнительная выручка может составить 279 и 442 руб. соответственно. The research aimed at testing the effect of chemical and biological preservation when ensiling alfalfa. Green mass was collected at the budding stage. Application rate — 5 l/t. Preparation were composed of either the mixture of lactic and propionic acid bacteria or organic acids. Intensity of biochemical processes was determined as water loss via gas formation. Preserving agents negatively affected biochemical reactions in silage. The bacterial preparation reduced gasification by 15.3%, chemical preservative — by 3.2 times. Row mass contained 2.26 MJ of exchange energy, untreated silage — 1.84, mass treated with the bacterial and chemical preparations — 1.96 and 2.06 MJ, respectively. Organic matter loss amounted to 14.7% in the control silage, exceeding bacterial and chemical ensiling by 1.24 and 4.17 times, respectively. The same tendency was observed for protein and nitrogen-free extractive substances. Bacterial agents provided exchange energy increase of 119.6 MJ per 1 t of silage mass, the chemical preparation — 246.4 MJ. Feeding cows with 1 t of experimental silage resulted in milk yield increase of 13.3 and 27.4 kg, additional revenue reached 279 and 442 RUB, respectively.

STUDY OF CHITINASE AND CHITINOLYTIC ACTIVITY OF LACTOBACILLUS STRAINS

The increasing consumer demand for less processed and more natural food products – while improving those products’ quality, safety, and shelf-life – has raised the necessity of chemical preservative replacement. Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Chitinolytic enzymes are of biotechnological interest, since their substrate, chitin, is a major structural component of the cell wall of fungi, which are the main cause of the spoilage of food and raw plant material. Among the several organisms, many bacteria produce chitinolytic enzymes, however, this behaviour is not general. The chitinase activity of the lactic acid bacteria is scarcely known and studied.The aim of the present study was to select Lactobacillus strains that have genes encoding chitinase, furthermore, to detect expressed enzymes and to characterise their chitinase activity. Taking into consideration the importance of chitin-bindig proteins (CBPs) in the chitinase activity, CBPs were also examined. Five Lactobacillus strains out of 43 strains from 12 different species were selected by their chitinase coding gene. The presence of the chitinase and chitin-biding protein production were confirmed, however, no chitinolytic activity has been identified.