Recent innovations in the production of selected specialty (non-traditional) beers

Customer demand for product diversity is the key driving force for innovations in the brewing industry. Specialty beers are regarded as a distinct group of beers different from two major types, lagers and ales, without established definitions or boundaries. Specialty beers, including low- to no-alcohol beer, low carbohydrate beer, gluten-free beer, sour beer, probiotic beer, and enriched beer, are exclusively brewed and developed keeping in mind their functionality, the health and wellbeing of the consumer, and emerging market trends. Compared with conventional beer-brewing, the production of specialty beers is technologically challenging and usually requires additional process steps, unique microorganisms, and special equipment, which in turn may incur additional costs. In addition, the maintenance of quality and stability of the products as well as consumer acceptability of the products are major challenges to successful commercialization. A harmonious integration of traditional brewing practices and modern technological approaches may hold potential for future developments. In the present review, latest developments in the fermentative production of selected specialty beers are discussed.

Photocatalytically Enhanced Inactivation of Internalized Pathogenic Bacteria in Fresh Produce Using UV Irradiation with Nano-Titanium Dioxide

ABSTRACT

Once pathogens are internalized in fresh produce, they pose a challenging food safety issue because they are not effectively inactivated by conventional rinsing or sanitization. To protect food safety and public health, the objectives of this study were to examine internalized levels of foodborne pathogens in different types of fresh produce and to investigate the effectiveness of photocatalytically enhanced inactivation of internalized pathogens in fresh produce using UV irradiation with titanium dioxide (TiO2). For this, green fluorescent protein-labeled Salmonella Typhimurium and Escherichia coli O157:H7 were inoculated on the leaf surface of four types of fresh produce (∼108 CFU per leaf), and varying concentrations of TiO2 suspension (0.50, 0.75, 1.00, 1.25, and 1.50 μg/mL) were applied to the surface of contaminated leaves. Depending on the nature of each vegetable, the internalized bacterial level differed (2 to 5 log CFU/g of leaf). When UV irradiation (6,000 J/m2) was applied, the internalized Salmonella Typhimurium and E. coli levels were reduced by 0.8 to 2.4 log CFU per leaf; with TiO2, the reduction was 1.1 to 3.7 log CFU per leaf. The inactivation efficiency increased as the TiO2 concentration increased (up to 1.50 μg per leaf). These results indicate that TiO2 application enhanced the photocatalytic inactivation of internalized foodborne pathogens. The application of TiO2 would be most practical before UV irradiation and before distributing the produce. This study established a platform for future research on the inactivation of various internalized pathogens for protecting public health and scaling up fresh produce treatments by the food industry.

HIGHLIGHTS

Decontamination of chokeberries (Aronia melanocarpa L.) by cold plasma treatment and its effects on biochemical composition and storage quality of their corresponding juices

To improve the microbiological quality of chokeberries, corona discharge plasma jet (CDPJ) was employed as a decontaminating agent. The mean levels of aerobic bacteria and yeast and molds contaminants in chokeberries were 4.78 and 4.87 log CFU/g, respectively; the viable counts were decreased by 2.09 and 1.83 log units following CDPJ treatment for 3 min, respectively. A first-order kinetic model was well-suited for explaining the inactivations. The concentration of total polyphenols of chokeberries was unaffected (up to 3 min treatment), whereas DPPH radical scavenging activity was significantly decreased by CDPJ treatment (2 min and more). CDPJ treatment (all tested times) of chokeberries led to a significant decrease of monomeric anthocyanin content of their corresponding juices, whereas soluble solids content (Brix) and pH were unaffected. After storage at 4 °C for 72 h, juices obtained from CDPJ-treated berries possessed relatively low levels of contaminants with no significant alterations in pH and soluble solids content when compared with controls. In conclusion, CDPJ treatment for 2 min was optimal to improve the microbiological quality of the berries without negatively affecting biochemical qualities of their corresponding juices.

Recent advances in biotechnological valorization of brewers' spent grain

Brewers' spent grain (BSG) is the most abundant by-product of beer-brewing. BSG is rich in nutrients such as protein, fiber, minerals, and vitamins, and therefore it is conventionally used as low-cost animal feed. On the other hand, alternative utilization of BSG has gained increased attention during recent years due to technological progress in its processing and the emergence of the concept of circular economy. The valorization of BSG through biotechnological approaches is environmentally friendly and sustainable. This review was focused on recent advancements in the conversion of BSG into value-added products, including bioenergy (ethanol, butanol, hydrogen, biodiesel, and biogas), organic acids, enzymes, xylitol, oligosaccharides, and single cell protein, via biotechnological approaches. In addition, the potential applications of BSG as immobilization matrices in bioprocesses have been reviewed.

Degradation of benzopyrene and acrylamide in roasted coffee beans by corona discharge plasma jet (CDPJ) and its effects on biochemical and sensory properties

This study was aimed to reduce the concentrations of benzopyrene (BaP) and acrylamide (ACR) in roasted coffee beans by corona discharge plasma jet (CDPJ). The initial concentrations of BaP and ACR in roasted beans were decreased by 53.6% and 32.0%, respectively, following CDPJ (powered by 20 kV DC/1.5 A) treatment for 60 min. The levels of total solid, total acid, chlorogenic acid, caffeine, trigonelline, and pH were insignificantly changed upon CDPJ treatment compared to controls. However, the concentration of total phenolic content and Agtron color values were altered significantly. The treatment of beans did not alter descriptive sensory properties of the corresponding coffee brews, except aroma and aftertaste characteristics. As the treatment time increased from 15 to 60 min, scores for aroma profiles in PCA plot were shifted from right to left, although overlapping was observed between 15- and 30-min-treated samples. Additionally, none of the treated samples were discriminated from the control by electronic tongue.

Decontamination of collards (Brassica oleracea var. acephala L.) using electrolyzed water and corona discharge plasma jet

Acidic electrolyzed water (AEW) was used for collards sanitization. In the AEW (pH of 3.6; 230 mg/L chlorine) generator, the rates of brine inflow and catholyte outflow were 2.73 and 442 mL/min, respectively. Following treatment of the collards with the AEW alone (5 min), the counts of aerobic bacterial contaminants were reduced by 1.91 log CFU/g, whereas 2.22 log CFU/g reduction was noted by the AEW soaking (5 min) followed by a corona discharge plasma jet treatment (1 min). In a similar manner, the counts of yeasts and mold contaminants were reduced (1.48 and 1.75 log CFU/g, respectively). The combination treatment exhibited an additive effect on the microbial inactivation. The combined treatment did not affect significantly the DPPH-radical scavenging activity and sensory properties (appearance, color and flavor) of the collards compared to negative controls. However, significant alterations in the levels of total phenolics and ascorbic acid were observed post-treatment.

Pulsed electric field (PEF) technology for microbial inactivation in low-alcohol red wine

The decontamination of spoilage-related microbes in low-alcohol red wine was performed using a serial multiple electrode pulsed electric field (PEF) treatment system. The system consisted of seven electrodes connected in series, and it has been designed to produce square-wave high-voltage pulses of 1 μs duration at various electric field strengths and frequencies for decontamination. The initial counts of aerobic bacteria, yeast and lactic acid bacteria (spoilage-associated microbes) in the wine were 5.56, 5.61 and 5.22 log CFU/mL, respectively. The pattern of decontamination of the spoilage microorganisms followed first-order kinetics and the decontamination effect increased as the field strength and frequency increases. DHz and DPEF values were inversely related to the electric field strength of the PEF treatment. The yeast exhibited relatively low DPEF-value than the aerobic and lactic acid bacteria. The lowest ZPEF-value was observed for the lactic acid bacteria (24.6 kV/cm) among the spoilage microbes.

Inactivation of spores by nonthermal plasmas

Bacterial and fungal spore contamination in different industries has a greater economic impact. Because of the remarkable resistance of spores to most physical and chemical microbicidal agents, their inactivation need special attention during sterilization processes. Heat and chemical sporicides are not always well suited for different sterilization/decontamination applications and carries inherent risks. In recent years, novel nonthermal agents including nonthermal plasmas are emerging as effective sporicides against a broad spectrum of bacterial and fungal spores. The present review discusses various aspects related to the inactivation of spores using nonthermal plasmas. Different types of both low pressure plasmas (e.g., capacitively coupled plasma and microwave plasma) and atmospheric pressure plasmas (e.g., dielectric barrier discharges, corona discharges, arc discharges, radio-frequency-driven plasma jet) have been successfully applied to destroy spores of economic significance. Plasma agents contributing to sporicidal activity and their mode of action in inactivation are discussed. In addition, information on factors that affect the sporicidal action of nonthermal plasmas is included.

Impact of corona discharge plasma treatment on microbial load and physicochemical and sensory characteristics of semi-dried squid (Todarodes pacificus)

The use of corona discharge plasma jet (CDPJ) for the improvement of the sanitary quality of semi-dried squid was investigated. Microbial contaminants, namely aerobic, coliforms, and molds and yeasts, were detected in the samples. The CDPJ generated using 20 kV DC voltage at 58 kHz frequency was used for the decontamination treatment (1-10 min). The bacterial contaminants and molds and yeasts were inactivated in the range of 1.5-2.1 and at 1.9 log CFU/g, respectively. The inactivation pattern was well fitted to the first-order kinetics model. The CDPJ treatment for 10 min did not exert significant changes (p > 0.05) in VBN and the trimethylamine content of semi-dried squid as compared to untreated controls. On the contrary, significant changes (p < 0.05) in moisture content, water activity, pH, color, and TBARS levels were observed upon plasma exposure. However, the CDPJ-treated samples displayed slightly better sensory properties than the controls in terms of appearance, visual color, and flavor.

Sustainable Methods for Decontamination of Microcystin in Water Using Cold Plasma and UV with Reusable TiO₂ Nanoparticle Coating

Microcystins (MCs) are a family of cyanotoxins and pose detrimental effects on human, animal, and ecological health. Conventional water treatment processes have limited success in removing MCs without producing harmful byproducts. Therefore, there is an urgent need for cost-effective and environmentally-friendly methods for treating MCs. The objective of this study was to develop sustainable and non-chemical-based methods for controlling MCs, such as using cold plasma and ultra violet (UV) light with titanium dioxide (TiO₂) coating, which can be applied for diverse scale and settings. MCs, extracted from Microcystis aeruginosa, were treated with cold plasma or UV at irradiance of 1470 μW/cm² (high) or 180 μW/cm² (low). To assess synergistic effects, the outside of the UV treatment chamber was coated with nanoparticles (TiO₂) prior to irradiation, which can be reused for a long time. The degradation efficiency of UV was enhanced by the reusable TiO₂ coating at lower irradiance (70.41% [UV] vs. 79.61% [UV+TiO₂], 120 min), but no significant difference was observed at higher irradiance. Cold plasma removed MCs rapidly under experimental conditions (92%, 120 min), indicating that it is a promising candidate for controlling MCs in water without generating harmful disinfection byproducts. It can be also easily and practically used in household settings during emergency situations.

Potential applications of nonthermal plasmas against biofilm-associated micro-organisms in vitro

Biofilms as complex microbial communities attached to surfaces pose several challenges in different sectors, ranging from food and healthcare to desalination and power generation. The biofilm mode of growth allows microorganisms to survive in hostile environments and biofilm cells exhibit distinct physiology and behaviour in comparison with their planktonic counterparts. They are ubiquitous, resilient and difficult to eradicate due to their resistant phenotype. Several chemical-based cleaning and disinfection regimens are conventionally used against biofilm-dwelling micro-organisms in vitro. Although such approaches are generally considered to be effective, they may contribute to the dissemination of antimicrobial resistance and environmental pollution. Consequently, advanced green technologies for biofilm control are constantly emerging. Disinfection using nonthermal plasmas (NTPs) is one of the novel strategies having a great potential for control of biofilms of a broad spectrum of micro-organisms. This review discusses several aspects related to the inactivation of biofilm-associated bacteria and fungi by different types of NTPs under in vitro conditions. A brief introduction summarizes prevailing methods in biofilm inactivation, followed by introduction to gas discharge plasmas, active plasma species and their inactivating mechanism. Subsequently, significance and aspects of NTP inactivation of biofilm-associated bacteria, especially those of medical importance, including opportunistic pathogens, oral pathogenic bacteria, foodborne pathogens and implant bacteria, are discussed. The remainder of the review discusses majorly about the synergistic effect of NTPs and their activity against biofilm-associated fungi, especially Candida species.

Effect of corona discharge plasma jet on surface-borne microorganisms and sprouting of broccoli seeds

BACKGROUND

Different pathogenic microorganisms have been reported to cause sprouts-associated outbreaks. In order to sterilise and enhance the germination of seeds, non-thermal plasma has been increasingly investigated in the field of agricultural science as an alternative to the traditional pre-sowing seed treatments. This work aimed to evaluate the effect of corona discharge plasma jet (CDPJ) on disinfection of the natural bio-contaminants of broccoli seed and also studied the plasma effect on sprout seed germination rate and physico-chemical properties of sprouts.

RESULTS

Aerobic bacteria, moulds and yeasts, B. cereus, E. coli, Salmonella spp. were detected on the broccoli seed surface. After 0-3 min treatment using CDPJ, the detected microorganisms were reduced in the range of 1.2-2.3 log units. Inactivation patterns were better explained using pseudo-first-order kinetics. The plasma treatment of seeds up to 2 min exhibited a positive effect on germination rate, seedling growth. The physico-chemical and sensory characteristics of sprouts were unaffected due to the CDPJ treatment of their respective seeds.

CONCLUSION

Corona discharge plasma jet can potentially be used for microbial decontamination of broccoli seeds. In addition, the plasma treatment of broccoli sprout seeds has enabled a significant enhancement in their germination rate and seedling growth without compromising physico-chemical and sensory characteristics of their corresponding sprouts. © 2016 Society of Chemical Industry.

Characteristics of yogurt-like products prepared from the combination of skim milk and soymilk containing saccharified-rice solution

Yogurt-like products were prepared from a combination of skim milk and soymilk (100:0, 75:25, 50:50, 25:75, and 0:100) containing saccharified-rice solution by lactic fermentation of four different cultures. The ratio of skim milk and soy milk had no significant effect on titratable acidity, while the type and nature of culture used for fermentation affected the titratable acidity. Lower syneresis was observed in soy-based yogurt, and both the hardness and springiness of curd increased as the proportion of soymilk in the substrate increased. Skim milk-based yogurt had higher resistance to shear force with higher yield stress. The sensory quality of yogurt produced from mixed culture had higher preference compared with that produced from a single culture (Streptococcus thermophilus). There was no significant difference in texture and overall acceptability among yogurts produced from mixed substrates and skim milk-based yogurt.

Saengshik, a formulated health food, prevents liver damage in CCl4-induced mice and increases antioxidant activity in elderly women

Saengshik is a Korean noncooked food made with of more than 30 different whole gains, vegetables, fruits, mushrooms, and seaweeds. All of these ingredients are frozen and dried to minimize the loss of nutrients. Saengshik has become popular among health-conscious people in the Republic of Korea. The study aims to investigate antioxidant effects of Saengshik by in vivo and human experiments. In in vivo tests, mice were fed Saengshik for 4 weeks, and oxidative damage was induced by CCl(4). Then the effects of Saengshik on oxidative damage were examined. It was found that plasma lipid hydroperoxide and protein oxidative damages were significantly suppressed and antioxidants, glutathione, and thiol groups were increased. The activity of the antioxidant enzyme superoxide dismutase was increased, and the level of glutamate pyruvate transaminase was decreased. In a human study, elderly people were given Saengshik for 24 weeks, and changes in antioxidant defense of the body were examined. Antioxidant activities in plasma were enhanced, although the difference was not significant. Therefore, it is expected that Saengshik is effective at removing oxidants from body tissues, preventing oxidative damage, and eventually boosting the antioxidant capacity of the body.

Adjunctive osteopathic manipulative treatment in women with depression: a pilot study

The authors assessed the impact of osteopathic manipulative treatment (OMT) as an adjunct to standard psychiatric treatment of women with depression. Premenopausal women with newly diagnosed depression were randomly assigned to either control (osteopathic structural examination only; n = 9) or treatment group (OMT; n = 8). Both groups received conventional therapy consisting of the antidepressant paroxetine (Paxil) hydrochloride plus weekly psychotherapy for 8 weeks. Attending psychiatrists and psychologists were blinded to group assignments. No significant differences existed between groups for age or severity of disease. After 8 weeks, 100% of the OMT treatment group and 33% of the control group tested normal by psychometric evaluation. No significant differences or trends were observed between groups in levels of cytokine production (IL-1, IL-10, IL-2, IL-4, and IL-6) or in levels of anti-HSV-1, anti-HSV-2, and anti-EBV antibody. There was no pattern to the osteopathic manipulative structural dysfunctions recorded. The findings of this pilot study indicate that OMT may be a useful adjunctive treatment for alleviating depression in women.

Characterization of a galactosyltransferase in purified bovine rod outer segments

Purified bovine rod outer segments (ROS) were used to study the transfer of labeled galactose from UDP-[3H]galactose to endogenous ROS glycoproteins, exogenous glycoproteins and N-acetylglucosamine (GlcNAc). The ROS reaction was also compared with that of the retinal microsomal fraction and milk galactosyltransferase. The results indicate that the ROS reaction was enhanced by exposure to light. Illumination, however, had no effect on the transfer of labeled galactose to either endogenous microsomal glycoproteins by retinal microsomal galactosyltransferase or the transfer of the sugar to ROS glycoproteins by milk galactosyltransferase. Manganese was most effective, followed by cobalt, as cofactor for the ROS enzyme. Calcium and magnesium produced about 60% of the activity observed with manganese. The ROS enzyme transferred minimal amounts of labeled galactose to asialo-agalactotransferrin or ovalbumin but readily transferred the sugar to GlcNAc. The latter reaction had an optimum pH of 6.3 and was linear for at least 90 min. It reached a maximum at about 30 mM GlcNAc and was inhibited by higher concentrations of the aminosugar and by low concentrations of alpha-lactalbumin. On the other hand, the transfer of galactose to ROS glycoproteins was not affected by low concentrations of alpha-lactalbumin. Our data suggest that the ROS galactosyltransferase may have a certain specificity towards its acceptor in the ROS. Its activation by light may indicate a role in the light-activated processes of the photoreceptor cell.

Effect of light on the transfer of sugars from sugar nucleotides to rod outer segment membranes of control and dystrophic rats

The transfer of N-acetyl-D-glucosamine (GlcNAc), D-mannose (Man), D-galactose (Gal) and L-fucose (Fuc) from their nucleotide complexes to isolated rod outer segment (ROS) membranes obtained from dark-adapted 21 +/- 2 days old dystrophic (RCS) and control (RCS-rdy+) rat retinas, was studied under light or dark conditions of incubation. It was found that all of these sugars were transferred to ROS membranes in the dark. Under these conditions there was significantly less (p less than 0.001) Gal transferred to dystrophic than to control membranes. Exposure to light affected the transfer of Gal and Fuc only. Thus, the transfer of Gal and Fuc to control ROS membranes was increased by about 50% compared to the level observed under dark conditions of incubation. On the other hand, exposure to light had no effect on the transfer of Gal to dystrophic ROS membranes but it enhanced the transfer of Fuc to these membranes by about 250% above the level observed in the dark. Under light there were highly significant (p less than 0.001) differences between control and dystrophic membranes in the transfer of Gal and Fuc. The transfer of Fuc to dystrophic ROS membranes was proportional to the concentration of GDP-Fuc but the acceptors on control membranes were saturated at low concentrations of substrate. However, the transfer of Gal from UDP-Gal to both types of membranes was proportional to the concentrations of substrate and ROS membrane protein and to the period of incubation. The transfer of Gal and Fuc to both types of membranes was significantly reduced after denaturation of ROS membrane proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a bovine hypothalamic extract on glucose utilization by rat adipocytes

This study was undertaken to assess whether a hypothalamic extract has any direct metabolic action on adipose and muscle tissues. An acid bovine hypothalamic extract (HE) was tested for its effect on the utilization of D[U-14C]glucose by isolated rat adipocytes and rat hemidiaphragms. The HE was ineffective in stimulating the conversion of labeled glucose into CO2 and glycogen by rat hemidiaphragm. However, in isolated adipocytes, the HE had significant lipogenic activity. This lipogenic effect was independent of insulin and nonsuppressible by insulin antibodies. The dose-response curve was linear and saturable. That insulin and the HE were not additive at maximal concentrations suggests that they act through a common rate-limiting step, possibly a receptor site. Other hypothalamic substances tested (thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, and substance P) showed no lipogenic activity. Somatostatin (6 microgram/ml) was an insulin potentiator but only when preincubated with the fat cells. It is concluded that the hypothalamic regulation of body weight may be mediated by a neurohumoral mechanism affecting adipose tissue stores.

Reactions of But-2-yne and Hexafluorobut-2-yne with Dicarbonyl(η-pentamethylcyclopentadienyl)-cobalt, -rhodium and -iridium. Structure of the iridium complex (η-C5Me5)Ir2(CO)2(CF3C2CF3)3H

The reactions of but-2-yne and hexafluorobut-2-yne with the complexes (η-C5Me5)M(CO)2, M = CO, Rh, or Ir, have been compared. A cyclopentadienone complex, (η-C5Me5)M[C4Me4CO]2 is the major product formed in the reaction of but-2-yne with (η-C5Me5)M(CO)2, M = Co or Rh. The cobalt system also gives some hexamethylbenzene whereas the rhodium system yields the pentadienone-dirhodium complex (q-C5Me5)2Rh2(MeC2Me)2CO. The cyclopentadienone complexes (η-C5Me5)M[C4(CF3)4CO], M = CO and Rh, were major products from the reactions of hexa- fluorobut-2-yne with (η-C5Me5)M(CO)2. Hexakis(trifluoromethyl)benzene and the tetrahapto- benzene complexes (η-C5Me5)M[η4-C6(CF3)6], M = Co or Rh, were minor products from these reactions. Small amounts of the dirhodium complexes (η-C5Me5)2Rh2(CF3C2CF3)2(CO)n, n = 1 or 2, were also isolated from the rhodium system under some reaction conditions. No products could be isolated from the reaction between (η-C5Me5)Ir(CO)2 and but-2-yne, but the reaction with hexafluorobut-2-yne gives two organoiridium complexes. One complex, (η-C5Me5)Ir(CO)2(CF3C2CF3), incorporates an iridiocyclobutenone ring and one terminal carbonyl. The second, (η-Ir5Me5)Ir2(CO)2(CF3C2CF3)3H, has been characterized crystallographically. The compound crystallizes with four molecules in the orthorhombic space group Pnma in a cell of di- mensions a 14.262(5), b 13.293(5), c 15.027(5) Ǻ. The structure has been refined by standard methods to a conventional R factor of 0.072, based on 2061 reflections above background. The environments of the two iridium atoms are markedly different. One forms part of a metallopentadiene ring, and it is also attached to two terminal carbonyls, a σ-bonded C(CF3)=C(CF3)H group, and the other iridium atom [Ir-Ir distance 2.737(1) Ǻ]. Overall, this iridium has a distorted octahedral geometry. The second iridium is n-bonded in a conventional sandwich manner to the C5Me5 and iridiocycle rings; these two rings have a staggered conformation and are close to parallel.

The reactions of some diynes with (C5H5)Co(CO)2 and Fe(CO)5: Inter- or Intra-molecular cyclizations?

The reactions of several diynes MeC≡C(CH2)nC≡CMe, n = 2-4, with (η- C5H5)Co(CO)2 and Fe(CO)5 have been compared. A p-benzoquinone complex, (η-C5H5)Co[(C8H10)2(CO)2], and three isomers of the cyclopentadienone complex, (η-C5H5)Co[(C8H10)2CO], are formed in the reaction of (η- C5H5)Co(CO)2 with octa-2,6-diyne. In each complex, the ligand is formed by intermolecular cyclization of two diynes with inclusion of CO. The corresponding reactions with nona-2,7-diyne and deca-2,8-diyne give complexes (η-C5H5)Co[(C9H12)CO] and (C5H5)Co[(C10H14)CO] in which a bicyclic cyclopentadienone has been formed by intramolecular condensation of the diyne. Intramolecular cyclization is also achieved when all three diynes are treated with Fe(CO)5. The reactions with octa- 2,6-diyne and deca-2,8-diyne give metallodiene complexes, Fe2(CO)6(diyne), in which the ferracyclopentadiene ring is fused to either a 4- or 6-membered ring. With nona-2,7-diyne, a cyclopentadienone complex of formula Fe(CO)3[(C10H14)CO] is isolated. In the reactions with Fe(CO)5,organic products of the type (diyne)2, (diyne)3 and [(diyne)CO]2 are also isolated.

Neuroendocrine control of insulin secretion

The effects of thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, substance P, somatostatin, and a partially purified hypothalamic extract on insulin secretion were tested both in vitro and in vivo. Only somatostatin and the hypothalamic extract affected insulin secretion. In vitro, somatostatin decreased glucose-stimulated insulin secretion by isolated islets and in vivo significantly reduced the rate of insulin output into the portal vein. The hypothalamic extract significantly stimulated insulin secretion in both systems. These effects in vivo were independent of glucose concentration. Islets preincubated for four hours responded better in vitro to the hypothalamic extract stimulation and the somatostatin inhibition.